Ed Feser responds to Sean Carroll

Ed Feser has a recent piece here.  I reproduce it below with comments interpolated.

People have been asking me to comment on the remarks about causation made by atheist physicist SeanCarroll during his recent debate with William Lane Craig on the topic of “God and Cosmology.”  (You’ll find Craig’s own post-debate remarks here.)  It’s only fair to acknowledge at the outset that Carroll cannot justly be accused of the anti-philosophical philistinism one finds in recent remarks by physicists Stephen Hawking, Lawrence Krauss, and Neil deGrasse Tyson.  Indeed, Carroll has recently criticized these fellow physicists pretty harshly, and made some useful remarks about the role of philosophy vis-à-vis physics in the course of doing so.
It is also only fair to note that, while I have enormous respect for Craig, I don’t myself think that it is a good idea to approach arguments for a First Cause by way of scientific cosmology.  I think that muddies the waters by inadvertently reinforcing scientism, blurring the distinction between primary (divine) causality and secondary (natural) causality, and perpetuating the false assumption that arguments for a divine First Cause are essentially arguments for a “god of the gaps.”  As I have argued many times, what are in my view the chief arguments of natural theology (i.e. Aristotelian, Neo-Platonic, Thomistic and other Scholastic arguments) rest on premises derived from metaphysics rather than natural science, and in particular on metaphysical premises that any possible natural science must presuppose.  For that reason, they are more certain than anything science itself could in principle ever either support or refute.  Arguments like Aquinas’s Five Ways, when properly understood (as, these days, they usually are not), no more stand or fall with the current state of play in scientific cosmology than they stand or fall with current gastroenterology or polymer research.  (See chapter 3 of Aquinas, my ACPQ article “Existential Inertia and the Five Ways,” my Midwest Studies in Philosophy article “The New Atheists and the Cosmological Argument,” and many other articles and blog posts.  Or, since we’re linking to YouTube, see my lectures “An Aristotelian Proof of the Existence of God” and “Natural Theology Must Be Grounded in the Philosophy of Nature, Not Natural Science.” )

Carroll’s remarks are largely directed at the question of whether scientific cosmologists should regard theism as a good explanation for the sorts of phenomena they are interested in, given the standard criteria by which models in physics are judged.  Since I don’t find that a terribly interesting or important question, I have nothing to say about his criticisms of Craig on that score.

Having said all that, Carroll’s remarks, where they touch on philosophical matters, are pretty shallow, and he does clearly think that what he has to say somehow poses a serious challenge to theism in general, not just theistic arguments grounded in scientific cosmology.  So those remarks are worth a response.  The key passage concerns Carroll’s criticism of Craig’s claim that “If the universe began to exist, then there is a transcendent cause which brought the universe into existence.”  Carroll says:

The real problem is that these are not the right vocabulary words to be using when we discuss fundamental physics and cosmology. This kind of Aristotelian analysis of causation was cutting edge stuff 2,500 years ago. Today we know better. Our metaphysics must follow our physics. That’s what the word “metaphysics” means. And in modern physics, you open a quantum field theory textbook or a general relativity textbook, you will not find the words “transcendent cause” anywhere. What you find are differential equations. This reflects the fact that the way physics is known to work these days is in terms of patterns, unbreakable rules, laws of nature. Given the world at one point in time we will tell you what happens next. There is no need for any extra metaphysical baggage, like transcendent causes, on top of that. It’s precisely the wrong way to think about how the fundamental reality works.  The question you should be asking is, “What is the best model of the universe that science can come up with?” By a model I mean a formal mathematical system that purports to match on to what we observe. So if you want to know whether something is possible in cosmology or physics you ask, “Can I build a model?”

End quote.  Now, it would take a book to explain everything that’s wrong with this.  And as it happens, I’ve written such a book; it’s called Scholastic Metaphysics: A Contemporary Introduction.  Since I’ve already said so much about these issues both in that book and elsewhere, I’m not going to repeat myself at length.  Let me just call attention to the key begged questions, missed points, and non sequiturs in Carroll’s remarks.

Well, of course this is 'wrong' from Ed's Aristotelian point of view.  But there is hardly any point in his saying it.  Carroll simply has a rival metaphysics.  The only sensible criticisms of a metaphysics are internal ones, from consistency, say, or external ones from relative explanatory power, say.  I will try to bring this out as we go through the post.  But it enables Ed to get in a neat puff for his latest book. 

Carroll tells us that explanation in physics proceeds by way of building a “model” that describes a “mathematical system” reflecting “patterns, unbreakable rules, laws of nature.”  Fine and dandy; I’ve pointed this out many times myself.  If Carroll’s point were merely that, to the extent that theism can’t be formulated in such mathematical terms, it just isn’t the sort of thing the physicist will find a useful explanation for the specific sorts of phenomena he’s interested in, then I wouldn’t necessarily have any problem with that.  That’s not what classical theism, properly understood, is all about in the first place.

But Carroll goes beyond that.  When he says that once you’ve hit upon the best mathematical model, whatever it turns out to be, “there is no need for any extra metaphysical baggage… on top of that,” he evidently means not just that you don’t need anything more for the purposes of physics, specifically, but that you don’t need anything more than that, period.  For he says that asking for more is “precisely the wrong way to think about how the fundamental reality works” and that “our metaphysics must follow our physics.”  The idea seems to be that once you’ve answered all the questions in physics, you’ve answered all the questions that can be answered, including all the metaphysical questions.  There’s nothing more to be done, not just nothing more for the physicist to do.

Now, why should anyone believe that claim (which is essentially just a version of scientism)?  Carroll gives no argument for it at all; he just asserts it with confidence.  This is a step down from Alex Rosenberg, who in The Atheist’s Guide to Reality did give an argument for a similar claim -- an argument which, as we saw, is extremely bad, but is at least still an argument. 

I'm not sure Carroll is being scientistic here at all.  It's just that as physics has developed over the past three hundred years, and as it has investigated the behaviour of matter on smaller and smaller scales, the concept of cause has disappeared from the subject.  In its place came, as Carroll says, differential equations.  These merely describe, in a general way, how matter behaves at small scale.  Taking such descriptions as axiomatic, we infer the behaviour of matter at macroscopic scales.  This is now seen as explanatory of macroscopic behaviour and replaces the common sense notion of causation.  The physics of the early twentieth century taught us that the behaviour of matter at the atomic scale simply cannot be understood by projecting the behaviour of macroscopic bodies onto smaller and smaller pieces of matter.  The atomic world is not the everyday world writ very small.  We cannot understand the small in terms of the large.  But we can understand the large in terms of the small.  So physics has abandoned causes.  The metaphysics of cause, central to an earlier Aristotelianism, is redundant.  All that is left is a ghost of formal causation to be found in the differential equations.

Nor could there be a good argument for Carroll’s scientism, because scientism is demonstrably false.  For one thing, “scientism” is more poorly defined than Carroll claims theism is.  However we tighten up our definition of notions like “science,” “physics,” and the like, the resulting scientism is going to be either self-refuting (since it will turn out that scientism cannot itself be established via the methods of physics or any other natural science), or completely trivial (since, to avoid the self-refutation charge, “science,” “physics,” etc. will have to be defined so broadly that even the metaphysical notions Carroll wants to dismiss will count as “scientific”). 

This is not the place to discuss that all-weather put-down,  'scientism'.  I do not concede that Carroll is being scientistic.  In any case, nobody is going to advance a 'demonstrably false' thesis.  That which is demonstrably false is not that which those accused of scientism are advocating.  A topic for another post perhaps. 

For another thing, to suppose that since physics confines itself to mathematical models, it follows that there is nothing more to reality than is captured by such models, is fallaciously to draw a metaphysical conclusion from a mere methodological stipulation.  The problem is not just that, if there are features of reality which cannot be captured in terms of a mathematical model, then the methods of physics are guaranteed not to capture them (though that is bad enough).  It is that there must in fact be more to reality than is captured by those methods, in part because (as Bertrand Russell noted) physics gives us only structure, and structure presupposes something which has the structure and which a purely structural description will of necessity fail to capture. 

This is interesting.  But Ed does not say what aspects of reality he has in mind, so we can't form a judgement as to whether this is relevant to physics or cosmology.  We can think of physics as the dynamics of matter in the small and cosmology as dynamics of matter at the very largest of scales.  If dynamics is the study of where the matter is over time, then it seems ripe for mathematical treatment.  What's the problem?

I develop these points in detail in Chapter 0 of Scholastic Metaphysics.  I also show, in that chapter and throughout the book, that the appeal to “laws of nature” so routinely and glibly made by naturalists like Carroll, simply does not and cannot do the work they suppose it does, and papers over a mountain of begged metaphysical questions.  In fact the very notion is fraught with philosophical difficulty, as writers like Nancy Cartwright and Stephen Mumford have shown.  As I have noted many times, the notion of a “law of nature” was originally (in thinkers like Descartes and Newton) explicitly theological, connoting the decree of a divine lawmaker.  Later scientists would regard this as a metaphor, but a metaphor for what?  Most contemporary scientists who pontificate about philosophical matters not only do not have an answer but have forgotten the question.

Allow me to pontificate.  Whatever 'law of nature' may have meant in the past, the phrase now, if it is used at all, merely refers to the differential equations which are thought to encode the patterns of possible motions.  They thus have the status of axioms.  One can ask, I guess, philosophical questions about axiomatic mathematical and physical theories, but I don't see how the concept of 'divine lawmaker' possibly fits into this, nor do I see a 'mountain of begged metaphysical questions'.  Such questions only arise against a background of metaphysical assumptions such as Ed's Aristotelianism.  Quite sensibly, in my view, Carroll simply refuses to talk this language.

One contemporary scientist who does see the problem is physicist Paul Davies, who, in his essay “Universe from Bit” (in Paul Davies and Niels Henrik Gregersen, eds. Information and the Nature of Reality: From Physics to Metaphysics), writes:

The orthodox view of the nature of the laws of physics contains a long list of tacitly assumed properties.  The laws are regarded, for example, as immutable, eternal, infinitely precise mathematical relationships that transcend the physical universe, and were imprinted on it at the moment of its birth from “outside,” like a maker’s mark, and have remained unchanging ever since… In addition, it is assumed that the physical world is affected by the laws, but the laws are completely impervious to what happens in the universe… It is not hard to discover where this picture of physical laws comes from: it is inherited directly from monotheism, which asserts that a rational being designed the universe according to a set of perfect laws.  And the asymmetry between immutable laws and contingent states mirrors the asymmetry between God and nature: the universe depends utterly on God for its existence, whereas God’s existence does not depend on the universe…

Clearly, then, the orthodox concept of laws of physics derives directly from theology.  It is remarkable that this view has remained largely unchallenged after 300 years of secular science.  Indeed, the “theological model” of the laws of physics is so ingrained in scientific thinking that it is taken for granted.  The hidden assumptions behind the concept of physical laws, and their theological provenance, are simply ignored by almost all except historians of science and theologians.  From the scientific standpoint, however, this uncritical acceptance of the theological model of laws leaves a lot to be desired… (pp. 70-1)

Now the naïve atheist reading this blog for the first time may suppose that at this point I am going to exclaim triumphantly that there cannot be law without a lawgiver and proclaim victory for theism.  But in fact, like Davies I don’t accept the theological account of laws.  I think it is bad metaphysics and bad theology (insofar as it tends toward occasionalism).  I want rather to make the following two points.  First, when scientists like Carroll confidently proclaim that we can explain such-and-such in terms of the laws of physics rather than God, what they are saying, without realizing it, is: “The explanation isn’t God, it’s rather the laws of physics, where ‘law of physics’ originally meant ‘a decree of God’ and where I don’t have any worked-out alternative account of what it means.”  Hence the “alternative” explanation, when unpacked, is really either a tacit appeal to God or a non-explanation.  In short, either it isn’t alternative, or it’s not an explanation.  The utter cluelessness of this stock naturalistic “alternative explanation” would make of it an object of ridicule if it were not so routinely and confidently put forward by otherwise highly intelligent, educated, and widely esteemed people.

Well, I do have an account of what 'law of physics' means.  It means a mathematical description of the behaviour of the simplest constituents of matter.  Just what Galileo sought in his experiments with inclined planes.  Together with principles of composition, such descriptions are explanatory of the behaviour of complex organisations of matter by means of deductive inference.  What, pray, is ridiculous about this?

Second, the original, explicitly theological Cartesian-Newtonian notion of “laws of nature” was intended precisely as a replacement for the Aristotelian-Scholastic metaphysics of nature.  The Scholastics held that the regularities in the behavior of natural phenomena derived from their immanent essences or substantial forms, and the directedness-toward-an-end or immanent teleology that followed upon their having those forms.  In other words, regularities reflected the formal and final causes of things.  The early moderns wanted to get rid of formal and final causes as immanent features of nature, and thus replaced them with the notion of “laws of nature” conceived of as externally imposed divine decrees.  To keep talk of “laws of nature” while throwing out God is thus not to offer an alternative to the Aristotelian-Scholastic view at all, but merely to peddle an uncashed metaphor.  So, whereas Carroll glibly asserts that “now we know better” than the Aristotelians did, what is in fact that case is that Carroll and other contemporary naturalists have not only chucked out Aristotelian metaphysics but have also chucked out the early moderns’ initial proposed replacement for Aristotelian metaphysics, and have offered nothing new in its place.  This is hardly a problem for the Aristotelian; on the contrary, it is a problem for anyone who wants to dismiss Aristotelian metaphysics.

Aristotle has a shallow physics and a deep metaphysics.  We moderns have the reverse.  The sense in which 'we now know better' is that our experience of the world is wider.  Telescopes can see to the ends of the universe and particle accelerators can look inside nucleons.  Neither space, time, nor matter are what they seem to the naked eye.  In one sense contemporary physics is itself a replacement for Aristotle's metaphysics.  For another way, see below.

Like other contemporary Aristotelians, I would say that the right way to interpret a “law of nature” is as a shorthand description of the way a thing tends to operate given its nature or substantial form.  That is to say, “laws of nature” actually presuppose, and thus cannot replace, an Aristotelian metaphysics of nature.  (Again see the discussion of the metaphysics of laws of nature in Scholastic Metaphysics.)  There are other accounts of laws, such as Platonic accounts and Humean accounts, but these are seriously problematic.  Platonic accounts, which treat laws of nature as abstract entities in a Platonic heaven, push the problem back a stage.  To appeal to such-and-such Platonic laws as an explanation of what happens in the world only raises the further problems of explaining why it is those laws rather than some others that govern the world, and what makes it the case that any laws at all come to be instantiated.  Humean accounts, meanwhile, interpret a law as a statement that such-and-such a regularity holds, or would have held under the right conditions.  But in that case an appeal to laws doesn’t really explain anything, but only re-describes it in a different jargon. 

Consider, in light of these points, what Carroll says about causation later on in the debate:

Why should we expect that there are causes or explanations or a reason why in the universe in which we live? It’s because the physical world inside of which we’re embedded has two important features. There are unbreakable patterns, laws of physics -- things don’t just happen, they obey the laws -- and there is an arrow of time stretching from the past to the future. The entropy was lower in the past and increases towards the future. Therefore, when you find some event or state of affairs B today, we can very often trace it back in time to one or a couple of possible predecessor events that we therefore call the cause of that, which leads to B according to the laws of physics.  But crucially, both of these features of the universe that allow us to speak the language of causes and effects are completely absent when we talk about the universe as a whole.  We don’t think that our universe is part of a bigger ensemble that obeys laws.  Even if it’s part of the multiverse, the multiverse is not part of a bigger ensemble that obeys laws.  Therefore, nothing gives us the right to demand some kind of external cause.

End quote.  Now in fact it is Carroll who has said absolutely nothing to establish his right to dismiss the demand for a cause as confidently as he does.  For he has simply begged all the important questions and completely missed the point of the main traditional classical theistic arguments (whether or not he has missed Craig’s point -- again, I’m not addressing that here).  One problem here is that, like so many physicists, Carroll has taken what is really just one species of causation (the sort which involves a causal relation between temporally separated events) and identified it with causation as such.  But in fact, the Aristotelian argues, event causation is not only not the only kind of causation but is parasitic on substance causation.

Carroll's remarks strike me as sensible.  They form, perhaps, the basis of an inchoate theory which sees (efficient) causation as just one way in which humans have attempted to conceptualise relations between objects and events.  A consequence, perhaps, of our evolved capacity to find pattern in the stream of sense data we each receive.  It is thus an element of the manifest but not the scientific image.  The case for seeing final causation this way is much more obviously made.  Material causation is readily assimilable to the scientific image, and so, as I suggest above, is formal causation.  Indeed, we can think of science as a vast elaboration of the notion of formal cause.  The diverse origins of material, efficient, formal and final cause under this view, suggest that they do not fall under a unified concept.

But put that aside, because the deeper problem is that Carroll supposes that causation is to be explained in terms of laws of nature, whereas the Aristotelian view is that this has things precisely backwards.  Since a “law of nature” is just a shorthand description of the ways a thing will operate -- that is to say, what sorts of effects it will tend to have -- given its nature or substantial form, in fact the notion of “laws of nature” metaphysically presupposes causation. 

Only within the Aristotelian metaphysical system.  Under the alternative system---which I guess counts as a metaphysics as it tries to explain why we think about the world along certain lines---the remaining three of the four causes are indeed subsumed under a version of formal causation.

Furthermore, what “allows us to speak the language of causes and effects” has nothing essentially to do with tracing series of events backwards in time.  Here again Carroll is just begging the question.  On the Aristotelian-Scholastic analysis, questions about causation are raised wherever we have potentialities that need actualization, or a thing’s being metaphysically composite and thus in need of a principle that accounts for the composition of its parts, or there being a distinction in a thing between its essence or nature on the one and its existence on the other, or a thing’s being contingent.  The universe, however physics and scientific cosmology end up describing it -- even if it turned out to be a universe without a temporal beginning, even if it is a four-dimensional block universe, even if Hawking’s closed universe model turned out to be correct, even if we should really think in terms of a multiverse rather than a single universe -- will, the Aristotelian argues, necessarily exhibit just these features (potentialities needing actualization, composition, contingency, etc.).  And thus it will, as a matter of metaphysical necessity, require a cause outside it.  And only that which is pure actuality devoid of potentiality, only what is utterly simple or non-composite, only something whose essence or nature just is existence itself, only what is therefore in no way contingent but utterly necessary -- only that, the classical theist maintains, could in principle be the ultimate terminus of explanation, whatever the specific scientific details turn out to be. 

We have come full circle.  From Ed's perspective Aristotelian metaphysical principles must indeed be presupposed by any possible natural science.  But we can equally well start from another point and see such principles as plausible modes of thought.  It is, perhaps, a matter of taste.

Carroll has not only not answered these sorts of arguments (which, again, I’ve only alluded to here -- see the various sources cited above for detailed defense).  He doesn’t even seem to be aware that this is where the issues really lie, and that they have nothing essentially to do with scientific cosmology.  But that’s not entirely his fault.  As I have indicated, in my view too many people (and not just Craig) put way too much emphasis on scientific cosmology where the debate between theism and atheism is concerned.  That just opens the door to objections like Carroll’s, since it makes it sound (wrongly, but understandably) like theism as such is essentially in competition with the sorts of models Carroll pits against Craig.

It seems to me that Ed can not or will not think outside the Aristotelian box.  He is just not open to the possibility of a new metaphysics that subsumes his own. 

That is not, by the way, to knock the kalām cosmological argument.  For (as Craig himself has emphasized) that argument need not appeal to scientific cosmology, but can be defended instead by way of appeal to more fundamental metaphysical premises.  (I have not had much to say about that argument myself because it is in my view less fundamental than the arguments I have focused on -- such as the Five Ways -- and there are, in any case, already many people writing about it.  If you’re looking for a Thomist’s defense of the kalām argument, you can’t do better than the relevant articles on the subject by David Oderberg.)

On Ostrich Nominalism

In Against Ostrich Nominalism  of 14 January 2013 Bill opens with
As magnificent a subject as philosophy is, grappling as it does with the ultimate concerns of human existence, and thus surpassing in nobility any other human pursuit, it is also miserable in that nothing goes uncontested, and nothing ever gets established to the satisfaction of all competent practitioners. (This is true of other disciplines as well, but in philosophy it is true in excelsis.) Suppose I say, as I have in various places:
That things have properties and stand in relations I take to be a plain Moorean fact beyond the reach of reasonable controversy. After all, my cat is black and he is sleeping next to my blue coffee cup. ‘Black’ picks out a property, an extralinguistic feature of my cat. 
Is that obvious? Not to some. Not to the ornery and recalcitrant critter known as the ostrich nominalist. My cat, Max Black, is black. That, surely, is a Moorean fact. Now consider the following biconditional and consider whether it too is a Moorean fact: 
1. Max is black iff Max has the property of being black. 
As I see it, there are three main ways of construing a biconditional such as (1):

A. Ostrich Nominalism. The right-hand side (RHS) says exactly what the left-hand side (LHS) says, but in a verbose and high-falutin' and dispensable way. Thus the use of 'property' on the RHS does not commit one ontologically to properties beyond predicates. (By definition, predicates are linguistic items while properties are extralinguistic and extramental.) Predication is primitive and in need of no philosophical explanation. On this approach, (1) is trivially true. One needn't posit properties, and in consequence one needn't worry about the nature of property-possession. (Is Max related to his blackness, or does Max have his blackness quasi-mereologically by having it as an ontological constituent of him?)
Bill then goes on to define two further construals of (1) which he calls ostrich realism and non-ostrich realism.  So far I'm an ostrich nominalist.  I can't better Bill's characterisation of the RHS of (1) as verbose, high-falutin, and dispensable.  However, he then says
On (A) there are neither properties, nor do properties enter into any explanation of predication. Predication is primitive and in need of no explanation. In virtue of what does 'black' correctly apply to Max? In virtue of nothing. It just applies to him and does so correctly. Max is black, but there is no feature of reality that explains why 'black' is true of Max, or why 'Max is black' is true. It is just true! There is nothing in reality that serves as the ontological ground of this contingent truth. Nothing 'makes' it true. There are no truth-makers and no need for any. 
Bill finds this preposterous.  But does it follow from (A)?  Can we hang on to the better part of (A)---avoiding the descent into the quagmire of the ontology of properties---yet escape the vacuity Bill finds?  I think so.  Let's change the example a little.  Suppose Max has his hind legs bent at the knee, his haunches on the floor supporting his weight, his spine inclined, and his forelegs straight and near vertical.  In these circumstances we would truly say 'Max is sitting' because 'sitting' is the right word to describe Max's attitude and the disposition of his limbs.  Would Bill want to say, Yes, Max is sitting, but there is no feature of reality that explains why 'sitting' is true of Max or why 'Max is sitting' is true?  I guess it depends on what kind of 'feature of reality' we are looking for.  If it has to be 'thing-like' then perhaps, yes, he would.  But it seems to me that we cannot capture reality by simply piling up things, despite the pressure language puts upon us to talk in terms of 'things'.  Is the problem that we can't analyse 'black' analogously to the analysis of 'sitting'?  Well, we could say that 'black' is the right word to describe the sensation caused in us by the light, or rather the paucity of light, reaching our eyes from Max.  But this clearly opens up a whole new realm of questions.  My inclination is to see this as a puzzle about language, not a puzzle about reality.

Searle's Rationality in Action

Just recently I came across a paper by William Hasker that cites a 2001 book by John Searle that I was unaware of.   Hasker quotes enough of Searle to seriously whet my appetite.  It should be arriving shortly.  In the meantime let me quote a big chunk from Hasker to explain my interest in Searle.

The anti-reductivism of most interest to us here is found in Searle’s recent book, Rationality in Action. Much of the argument of that book revolves around the notion of “the gap” that exists in all cases of rational action.  According to Searle, “‘The gap’ is the general name that I have introduced for the phenomenon that we do not normally experience the stages of our deliberations and voluntary actions as having causally sufficient conditions or as setting causally sufficient conditions for the next stage” (2001, p. 50). He also says, “The operation of rationality presupposes that there is a gap between the set of intentional states on the basis of which I make my decision, and the actual making of the decision” (p. 13). This gap is crossed by the activity of a “non-Humean self.” (“You cannot account for the rational self just in terms of a Humean bundle of disconnected perceptions” (p. 289).) The gap, according to Searle, is an obvious feature of everyday experience. Suppose you have gone to a restaurant, and the waiter asks for your order. You can’t just say, “Look, I am a determinist, che sarà, sarà. I will just wait and see what I order! I will wait and see what my beliefs and desires cause!” Searle continues, “This refusal to exercise my freedom is itself only intelligible to you as an exercise of freedom” (p. 14). Searle’s point here serves to underscore the failure of psychological determinism, as noted in the previous section of this essay. Important questions arise, however, when we attempt to combine this psychological account of human action with the neurobiological account. Searle queries, “There is no doubt that the gap is psychologically real, but is it otherwise empirically real? Is it neurobiologically real? If human freedom really exists, it must be a feature of brain function” (p. 269). Searle’s analysis of this question can be illustrated by a pair of diagrams. The first diagram illustrates the situation in which it is assumed that the agent’s reasons, consisting of her desires and beliefs, constitute a sufficient cause of the decision:
               deliberation on reasons           →                   decision

                       ↑  C&R                                                   ↑ C&R
                 neuron firings                      →                neuron firings                                  

One set of neuron firings “causes and realizes” (C&R) the deliberation, another set causes and realizes the decision, and the whole process is regarded as entirely deterministic. This way of conceptualizing the situation is quite similar to Kim’s supervenient causation, though Searle does not employ the language of supervenience. When we add the gap, however, the diagram must be altered:

                                                  causes with gaps    
               deliberation on reasons             →                  decision

                      ↑ C&R                                                      ↑ C&R
                neuron firings                    →                 neuron firings

Now the assumption is that “the indeterminacy at the psychological level is matched by a completely deterministic system at the neurobiological level” (p. 283). In Searle’s view, some distinctly uncomfortable conclusions emerge from this way of understanding action:
This result . . . is intellectually very unsatisfying because, in a word, it is a modified form of epiphenomenalism. It says that the psychological processes of rational decision making do not really matter. The entire system is deterministic at the bottom level, and the idea that the top level has an element of freedom is simply a systematic illusion. It seems to me at t1 that I have a choice between the Burgundy and the Bordeaux and that the causes operating on me are not sufficient to determine the choice. But I am mistaken. The total state of my brain at t1 is entirely sufficient to determine every bodily movement as well as every thought process from t1 to t2 to t3 . . . and the only thing we can say about psychological indeterminism at the higher level is that it gives us a systematic illusion of free will” (p. 285).
In addition to undermining our lived experience of free will, Searle states that
the hypothesis seems to me to run against everything we know about evolution. It would have the consequence that the incredibly elaborate, complex, sensitive, and – above all – biologically expensive system of human and animal conscious rational decision making would actually make no difference whatever to the life and survival of the organisms. (p.286).
Given these unwelcome consequences of the hypothesis of “psychological libertarianism with neurobiological determinism,” the situation is ripe for the emergence of a competing hypothesis, which takes the form of “system causation with consciousness and indeterminacy.” On this view, “the absence of causally sufficient conditions at the psychological level is matched by a parallel lack of causally sufficient conditions at the neurobiological level” (p. 286). But this in turn forces us to
examine critically the assumptions built into our diagrammatic representation with its metaphors of ‘bottom-up,’ ‘top-down,’ ‘levels of description,’ etc. . . . The problem is this: the idea that consciousness is a higher-level or surface feature of the brain gives us a picture of consciousness as like the paint on the surface of the table. . . . All of that is wrong. Consciousness is no more on the surface of the brain than liquidity is on the surface of the water. Rather the idea we are trying to express is that consciousness is a system feature. . . . What we have to suppose, if we believe that our conscious experience of freedom is not a complete illusion, is that the whole system moves forward toward the decision making, and toward the implementing of the decision in actual actions; that the conscious rationality at the top level is realized all the way down, and that means that the whole system moves in a way that is causal, but not based on causally sufficient conditions. (p. 287)
 Clearly, this second hypothesis involves extremely difficult metaphysical questions, which cannot be pursued further here. What is remarkable is that Searle has even proposed such a hypothesis, one which challenges the foundations of most contemporary thinking about the mind and the brain. Nevertheless, Searle himself is troubled by its implications, and states, “Frankly, I do not find either hypothesis intellectually attractive” (p. 296); he is unwilling to decide definitely between them. The problem he finds with the second hypothesis “is to see how the consciousness of the system could give it a causal efficacy that is not deterministic. And it is not enough help to be told that we could accept the randomness of quantum mechanical accounts that are not deterministic. Conscious rationality is not supposed to inherit the randomness of quantum mechanics.  Rather, conscious rationality is supposed to be a causal mechanism that proceeds causally, though not on the basis of antecedently sufficient causal conditions” (pp. 297- 98). Searle himself would be the first to admit that his non-reductivism is a work still in progress.

One possible cause of Searle's discomfort with the first of these viewpoints ('psychological libertarianism with neurobiological determinism')  is that he takes a realist position with regard to his 'reasons'.  I'm not sure that this is quite right.  Suppose we agree that the ordinary objects of the manifest image---trees and houses and people---are appearances arising in me from information arriving at my sense organs from the underlying elements---molecules and photons---of the scientific image.  Then it also makes sense to say that what we call 'reasons' are also appearances in me arising from my own brain's sensing of neurobiological activity within itself.  It is as if my mind looks simultaneously outwards on the world via my senses and inwards at itself and its own activity.  If the outer gaze can give rise to appearances which are in some sense 'approximations' or 'integrations'---I see small numbers of  continuously solid macroscopic objects rather than myriads of discrete particles---then so can the inner gaze integrate reasons from neural activity.  Certainly our reasons, whatever they may be neurobiologically, appear to us in the form of sentences.  I ask myself what reason I have for some act and I get a sentence.  Similarly with belief.  Searle's 'gap' may then arise in two ways.  Firstly, the neurological activity that bridges the gap may be taking place somewhere inaccessible to the inward gaze.  The internal sense organ receives no information from it just as the visual cortex knows nothing of the distribution of infra-red and ultra-violet incident upon me.  Secondly,  the many-one 'clumping' process that renders neurobiological activity into sentences may simply be inherently gappy.  There may be no way of learning how to map such activity onto the words of a shared language.  When I ask myself  how I decided beween reasons,  no sentence is forthcoming.

A design argument

Oh dear. Bill has just given an awful, Plantinga-inspired argument for theistic design. He can do better than this! Here's what he says:
1. It is rational to rely on our cognitive faculties to provide access to truths external to them.
2. It would not be rational to rely on our cognitive faculties if they had come about by an unguided process of natural selection operating upon random genetic mutations.
3. Our cognitive faculties did come about by an unguided process of natural selection operating upon random genetic mutations.
The limbs of the triad are individually plausible but collectvely inconsistent: they cannot all be true. From any two limbs one can validly argue to the negation of the remaining one. So, corresponding to our antilogism there are three valid syllogisms. One of them is a design argument that argues to the negation of (3) and the affirmative conclusion that behind the evolutionary process is intelligent, providential guidance. "And this all men call God."

To resist this design argument, the naturalist must reject either (1) or (2). To reject (2) is to accept the rationality of believing both that our cognitive faculties arose by accident and that they produce reliable beliefs. It is to accept the rationality of something that, on the face of it, is irrational. To reject (1) is not very palatable either. But I suppose one could bite the bullet and say, "Look, we are not justified in relying on our cognitive faculties, we just rely on them and so far so good."
Let's put to one side doubts that the presupposition that whether to rely or not on our cognitive faculties is a question of rational decision making.  Not to rely on our faculties condemns us to a brief life of frustration.  The naturalist will reject (2).   Our faculties may be accidental, in the sense of contingent,  but so is the Eiffel Tower.  And they may not have arisen without accidental events such as random genetic mutations.   But Bill ignores natural selection---the winnowing out of those mutations that diminish fitness relative to those that enhance it.  We have reason to think that natural selection and genetic mutation have built effective and reliable legs, hearts, and digestive systems.  Why not cognitive faculties too?

In a comment to the post Bill adds,
I am not confident about this topic, but I'll venture the following. I wonder whether reliable faculties are more conducive to reproductive fitness than unreliable ones. You will agree that reliability cannot be defined in terms of fitness. One cannot say that cognitive faculties are reliable just in case they lead to reproductive success.  As I understand it, reliable faculties are those that can be trusted to deliver truth more often than not. It may well be that false beliefs are more adaptive than true ones.
Well, reliable legs, hearts, and digestive systems seem to be more conducive to reproductive fitness than unreliable ones.  What reason has Bill to think that cognitive faculties fare any different?  And it would mean that God does deceive us.

Is and Ought

I have been following Bill's is/ought series of posts, starting here. I suggest that the examples considered so far can be put into a common form:
1.  Action A is a necessary condition of goal G.
2.  If I want to achieve goal G, then I ought to perform action A.
I hope everybody will agree that (1) is not normative.  It merely expresses the objective fact that the situation G isn't going to happen unless A is performed.  The ought in (2) expresses the necessity of A, the obligation of A for me that arises when I desire goal G.  I think it's important to notice that the obligation is conditional on the desire.  To will the end one must will the means.   But absent the desire, absent the necessity.

So my first point is that ought expresses a species of conditional necessity.  We can rearrange the above into a syllogistic form:
1.  I want to achieve G.
2.  Action A is a necessary condition of goal G. Ergo,
3.  I ought to perform A.
This seems  a very common pattern of practical reasoning.  It's clear I think that there can be no inference of (3) from (2) alone.  An argument that claims that (3) follows from (2) is enthymematic on (1).  And we can summarise this result by a general claim that a practical ought like (3) cannot be derived from an is like (2).

What about moral oughts?  My answer is to subsume them under practical oughts.  For this,  for any action A that is morally obligatory on me, I have to find a corresponding goal G that I desire. In many cases this goal will be simply to remain accepted within my moral community.  I pay the grocer's bill because I want to continue to be supplied with groceries.  This is my 'long stop', ultimate, goal that comes into play if no other goal takes precedence.   Of course, it may be that A is not necessary for this G.  Perhaps my failure to A will go undetected and I will be tempted into moral backsliding.  Then a more proximate goal of not appearing to myself as a moral backslider may appear.  Note that I'm not giving the circular argument that moral backsliding is immoral.  I'm saying that, no doubt through my moral upbringing, I do not wish to see myself as a backslider.  I can't offer an account as to why I have such a desire---this will no doubt have to be explained in terms of evolved moral sentiments and education---but for the purposes of this argument I need only say that I may have such a wish, and this desire generates the obligation.  Or, possibly, I am at odds with my moral community over some issue.  Perhaps, because of my moral formation, my desire to conform to some principle outweighs my fear of community ostracism.  If this motivation is uppermost, and A is necessary to realise it, then I will be obliged to A.

A final point.  There are two aspect here:  the necessity of A for G and its devolving on me because G is my goal.   The necessity here is ultimately a logical matter, a perceived that without which not.  So this little theory is consistent with my wider thesis that this is the only kind of necessity there is, or at least the only kind that we can grasp or make contact with.

Intellect versus imagination

Ed Feser has a piece out on Hume's reduction of the mental to the imagination in the course of which he refers us back to an earlier post comparing and contrasting the intellect and the imagination.  It's this earlier piece I'd like to discuss.
As Aristotelians and Thomists use the term, intellect is that faculty by which we grasp abstract concepts (like the concepts man and mortal), put them together into judgments (like the judgment that all men are mortal), and reason logically from one judgment to another (as when we reason from all men are mortal and Socrates is a man to the conclusion that Socrates is mortal).  It is to be distinguished from imagination, the faculty by which we form mental images (such as a visual mental image of what your mother looks like, an auditory mental image of what your favorite song sounds like, a gustatory mental image of what pizza tastes like, and so forth); and from sensation, the faculty by which we perceive the goings on in the external material world and the internal world of the body (such as a visual experience of the computer in front of you, the auditory experience of the cars passing by on the street outside your window, the awareness you have of the position of your legs, etc.).
That intellectual activity -- thought in the strictest sense of the term -- is irreducible to sensation and imagination is a thesis that unites Platonists, Aristotelians, and rationalists of either the ancient Parmenidean sort or the modern Cartesian sort.  The thesis is either explicitly or implicitly denied by modern empiricists and by ancients like Democritus; as I noted in an earlier post, the various bizarre metaphysical conclusions defended by writers like Berkeley and Hume largely rest on the conflation of intellect and imagination.  But the irreducibility of intellect to imagination is for all that undeniable, for several reasons.
Ed claims Berkeley and Hume conflate intellect and imagination. Ed treats them as of different kinds. I will try to show that the distinction is not as sharp as Ed suggests.

Thinking versus imagining

First, the concepts that are the constituents of intellectual activity are universal while mental images and sensations are always essentially particular.  Any mental image I can form of a man is always going to be of a man of a particular sort -- tall, short, fat, thin, blonde, redheaded, bald, or what have you.  It will fit at most many men, but not all.  But my concept man applies to every single man without exception.  Or to use my stock example, any mental image I can form of a triangle will be an image of an isosceles, scalene, or equilateral triangle, of a black, blue, or green triangle, etc.  But the abstract concept triangularity applies to all triangles without exception.  And so forth.
Second, mental images are always to some extent vague or indeterminate, while concepts are at least often precise and determinate.  To use Descartes’ famous example, a mental image of a chiliagon (a 1,000-sided figure) cannot be clearly distinguished from a mental image of a 1,002-sided figure, or even from a mental image of a circle.  But the concept of a chiliagon is clearly distinct from the concept of a 1,002-sided figure or the concept of a circle.  I cannot clearly differentiate a mental image of a crowd of one million people from a mental image of a crowd of 900,000 people.  But the intellect easily understands the difference between the concept of a crowd of one million people and the concept of a crowd of 900,000 people.  And so on.
There is a degree  of tension between these two paragraphs.  The first says that any mental image is essentially particular and the second says any mental image is to some extent vague or indeterminateThe first says that a concept applies to every instance without exception and the second says that not all concepts are precise and determinate.  There is a certain surface plausibility to what Ed says, but on digging deeper we find that it's not that simple.  For example, we can visualise the chiliagon by imagining it scaled up so that each side was a single pace in length, and then imagining ourselves walking round it while counting our paces. Likewise, we can imagine our one million people each walking to a preassigned square in a grid one thousand metres on a side.  One might argue that this visual imagining has an intellectual element, and I'd agree.  I think the two are inseparable.  The reason for this is that as soon as we have any kind of image before our minds, intellectual processes of bringing that image under concepts, as it were, are set in motion.  And this conceptualisation will itself involve corresponding imagery.  It's quite difficult to inhibit this intellectualisation.  Perhaps experienced meditators can do this.  Picasso once said that he wanted to see the world as children do.  See next comment.
Third, we have many concepts that are so abstract that they do not have even the loose sort of connection with mental imagery that concepts like man, triangle, and crowd have.  You cannot visualize triangularity or humanness per se, but you can at least visualize a particular triangle or a particular human being.  But we also have concepts -- such as the concepts law, square root, logical consistency, collapse of the wave function, and innumerably many others -- that can strictly be associated with no mental image at all.  You might form a visual or auditory image of the English word “law” when you think about law, but the concept law obviously has no essential connection whatsoever with that word, since ancient Greeks, Chinese, and Indians had the concept without using that specific word to name it.  You might form a mental image of a certain logician when you contemplate what it is for a theory to be logically consistent, or a mental image of someone observing something when you contemplate the collapse of the wave function, but there is no essential connection whatsoever between (say) the way Alonzo Church looked and the concept logical consistency or (say) what someone looks like when he’s observing a dead cat and the concept wave function collapse
There is a spurious definiteness to this, I feel.  What is the step from man and triangle, say, which Ed agrees do support loose mental imagery, to humanness and triangularity which supposedly do not?  I can visualise a particular triangle or person---I can try to recall 'in my mind's eye' how they look, but I think I can visualise a triangle or a person, 'in general', as it were.  More needs to be said on this.  I also have visual imagery for Ed's examples of square root, logical consistency, and collapse of the wave function.  Less so of law.  So things are not as clear-cut as Ed suggests and there is room for variation between thinkers.  Richard Feynman somewhere describes a method he had for grasping abstruse mathematical assertions by elaborate visual imagery.  It would be better to say that, starting with the most determinate and particular of visual images, say that of a triangular object before us, we can choose successively to ignore aspects like size, colour, texture, possession of an interior, shape, to arrive at an abstract visual image of a triangle.  Likewise we can go from a rich description of our object to a more meagre description by a successive dropping of descriptive elements.   It seems that these processes run in parallel, each reinforcing the other, one in visual space, as it were, and the other in conceptual space.  Rather than pull them apart, as Ed wants to do, perhaps we should see two aspects of a single process.  

The impossibility of materialism

Now, the reason why intellectual activity cannot in principle be reduced to sensation or imagination is, as it happens, related to the reason why intellectual activity cannot in principle be reduced to, or entirely supervenient upon, or in any other way explicable in terms of material processes of any sort.  For like mental images, the symbols postulated by cognitive scientists (“sentences in the head,” “maps,” or what have you), and any other possible purported material embodiments of thought, (a) necessarily lack the universality that concepts have, (b) necessarily lack the determinacy that concepts have, and (c) generally have exactly the loose and non-essential connection to the concepts they purportedly embody that the word “law” has to the concept law or a mental image of Alonzo Church has to the concept logical consistency.
Contra (a), one might see a universal as a pattern,  and we know that material systems can detect patterns.
Contra (b), some concepts seem rather indeterminate---Wittgenstein's 'game', for example---whereas some physical systems can be pretty determinate in some respects.  There is exactly one hole in a torus, for example.  Any tangle of string is either definitely knotted or definitely unknotted. 
(c)  begs the question, I think.  Ed is saying that the only possible substrate for intellectual activity is the wholly inadequate visual imagery.  I deny this.  See contra (a).
There is no way the materialist is ever going to square this circle.  To “explain” intellectual activity entirely in terms of material processes is inevitably at least implicitly to deny the existence of the former, or of some essential aspect of the former.   For instance, if you identify thought with material processes, you are necessarily committed to denying, implicitly or explicitly, that our thoughts ever really have any determinate content.  A number of materialists have seen this -- Quine, Dennett, and Bernard Williams are three examples -- and have decided to bite the bullet and accept that the content of all thought and language is inherently indeterminate.  (This is, for instance, the upshot of Quine’s famous “indeterminacy of translation” and “inscrutability of reference” theses and of Dennett’s “two-bitser” example.)
It seems to me that our thought falls on a spectrum of indeterminacy.  In general it need be only as determinate as the business of life requires.  What does it matter that I cannot closely specify the meaning of 'game'?  'There's a bear in the cave!' is sufficiently indefinite to conjure up the image of a bear on the doorstep.   It certainly seems reasonable to me to accept Quine's indeterminacy of translation and inscrutability of reference, given that the information content of a sentence is tiny in comparison to the information content of a brain.  But it's absurd to say that the degree of indeterminacy makes communication worthless.   Dennett's 'two-bitser' example shows, I think, that the notion of 'purpose' is agent-relative and hence to some extent indeterminate.  How far this extends  to the idea that physical states have indeterminate meaning, I am not sure.  One distinction which is not made, I think, is between interpreting some state as an outside observer, and actually being in that state.  However, Dennett's claim is that our intentionality is derived rather than original and is thus potentially indeterminate, not necessarily indeterminate.  See next comment regarding arithmetic.
But such claims are indefensible, for reasons James Ross has trenchantly spelled out.  First, if you deny the determinacy of thought, there is no way you will be able to make sense of the vast body of knowledge embodied in mathematics and logic, all of which presupposes that we have determinate concepts.  And there will in that case be no way you will be able to make sense of empirical science, which presupposes mathematics and logic, and in the name of which these materialists endorse their indeterminacy theses.  Second, if you deny the determinacy of thought, then you are committed to denying that we ever determinately think in accordance with valid forms of inference -- modus ponens, modus tollens, etc. -- or that we ever really add, subtract, multiply, etc.  You have to hold that we only seem to do so.  But that entails that we never in fact reason logically or in mathematically sound ways.  This not only (once again) makes science unintelligible, but it also undermines absolutely every argument anyone has ever given, including every argument for materialism.  Third, even to deny that our thoughts ever have a determinate content -- for example, to deny that we ever determinately employ addition as opposed to Saul Kripke’s notion of “quaddition” -- you first have to grasp what addition is and then go on to deny that we ever do it.  But that means that you must have a thought with a certain determinate content even to deny that you ever have thoughts with that specific content.
Well, we disagree over what Ross has shown.   With regard to Ross's discussion of arithmetic it's perhaps worth noting that any model of the Peano axioms contains an initial segment isomorphic to the natural numbers.  So in so far as my concept 'plus' satisfies the Peano axioms that concept appears to be constrained in its meaning to the plus of arithmetic.  I think Ed would agree that mathematical and logical concepts are highly abstract and in some sense epitomise the intellect.  But interestingly, it's just these mathematical and logical concepts that are amenable to mechanisation.  Proofs can be found and checked by computer.  What does this tell us about the upper reaches of the intellect?
So, anyone who thinks that thought can even in principle be entirely material hasn’t thought carefully enough about the nature of thought.  The materialist refutes materialism every time he so much as tries to argue for it.  Or so I would argue, and have argued at length elsewhere (e.g. in chapter 7 of Philosophy of Mind, chapter 4 of Aquinas, and at greatest length in my forthcoming American Catholic Philosophical Quarterly article “Kripke, Ross, and the Immaterial Aspects of Thought”).  But I’m not going to say anything more about that subject here, because it’s not relevant to the point I do want to make in this post.  So, if you want to insist that intellectual activity is material, then fine, that’s another subject.  The point for present purposes is that thinking in the strict sense -- grasping abstract concepts, formulating propositions, reasoning from one proposition to another -- is different from forming mental images or the like (even if it is somehow material in some other way).
I think that the argument that's trying to get out here, that intellect does not reduce to imagery, requires the Aristotelian premise that sensation and imagination are indeed material processes whereas the intellect is not.

Science is an essentially intellectual activity

Now everyone knows that this is true where physics and mathematics are concerned.  Of course, we do find it useful to form mental images when we try to grasp the abstractions of these disciplines, at least initially.  We draw geometrical figures on paper, think of points as little dots and of lines as the sort of thing you might draw with a ruler, imagine particles as little round objects moving about and of the structure of spacetime as like a rubber sheet we might twist around in different shapes.  But none of this is strictly correct, and the deeper we understand the concepts involved, the more we see that these visual images are just crude approximations.  That’s why physicists prefer to put things in mathematical terms.  They are not trying to show off or to be difficult for the sake of difficulty.  It is rather that it is precisely those aspects of nature which can be modeled mathematically that they are interested in as physicists.  Hence to put their ideas in non-mathematical terms simply fails to get at the essence of what it is they are trying to describe.  (The mistake some of them make is in assuming that a mathematical description exhausts nature, as opposed to capturing merely an aspect of nature.  But that’s a different subject, which I have addressed here, here, and here.)
Maybe the physics of particles and fields does exhaust what can be said about nature at this level of description.  Perhaps point particles like quarks and leptons really do have just the properties physics says they have.   The rest is emergent.  Even extension is an emergent property of ensembles of interacting point particles.  But yes.
This was part of the point of Descartes’ consideration of the possibility that he might be dreaming when he thinks he’s awake, or that the world of his senses might be a hallucination put into his consciousness by an evil spirit.  He was not interesting in providing fodder for college dorm room bull sessions or science-fiction screenwriters.  Nor was he merely interested in raising and responding to the problem of epistemological skepticism.  What he was trying to do was reinforce the idea that physics as he wanted to (re)define it -- and he was one of the fathers of modern science, as well as being the father of modern philosophy -- is something that can be understood only via the intellect, and not via the senses or the imagination.  Even if physical theory must be tested via empirical observation, its content is something that is expressible only in highly abstract terms that we must grasp with the intellect rather in terms of what we can imagine or perceive.  As with the concepts law and logical consistency (to cite some examples given above), any mental imagery we associate with the concepts we learn from a physics textbook are bound to be misleading and will have little or no essential connection to the realities to which the concepts correspond.  That is precisely why modern physics is so hard -- it requires a degree of abstraction of which few are capable.
I'm not sure Ed is on firm ground with these remarks on Descartes.  Surely the 'mechanical philosophy' is to be understood through the senses of touch and kinaesthesia---the push and pull of mechanical forces---in contrast with the abstractions of Aristotelianism?  But yes, modern physics rests on highly abstract mathematics.

Philosophy and theology are also essentially intellectual activities 

Now the key concepts of the great systems of metaphysics -- whether Platonic, Aristotelian, Thomistic or other Scholastic systems, or modern rationalist systems like those of Descartes and Leibniz -- are also of the sort that can be grasped only via a high degree of intellectual abstraction, with little or nothing in the way of assistance by mental imagery.  Indeed these concepts are if anything of an even higher degree of abstraction than those dealt with by the physicist.  For many of them concern not just material being, nor even the most abstract aspects of material being, but being as such.  When the metaphysician inquires into the nature of existence, or essence, or causation, he wants to know not merely what it is for this or that material thing to exist or have a nature or have a cause, nor even merely what it would be for some particular immaterial thing to exist or to have a nature or a cause.  He also wants to know what existence as such is, what causation as such is, and so forth.  His enterprise requires taking the mind as far from mental imagery -- as far from what we can visualize, for example -- as it can possibly go.  Thus, while metaphysics does not involve complex calculations or the like, it is in another respect even more difficult than physics insofar as it requires an even greater sustained effort of abstraction.
Yes, and it's a high-wire act without a safety net.  No way of checking that these ratiocinations haven't gone wrong.   On the other hand, the mathematics of theoretical physics is checkable, by machine if necessary, and its physical interpretation is subject to empirical test.  The metaphysician may ask what existence as such is, but does this question make any sense?  We move from 'to exist', which looks like a verb, to 'existence' which looks like a noun, and we can ask of any thing what it is, so the question What is existence? is grammatically well-formed.  It's just that we seem to have lost touch with solid ground, just like a cartoon character running off  a cliff.  See next comment.
Hence, when it is said by the Scholastic philosopher or theologian that God is pure actuality, subsistent being itself, and absolutely simple, or that the human soul is the substantial form of a living human being, you are going to misunderstand these concepts completely if you think of them as literally having anything to do with what you can visualize in your mind’s eye.  For example, if you think of an explosion (say) when you think of God qua Actus purus actualizing the world, or of a tiny marble-like object when you think of absolute simplicity, or the dotted-line outline of a body when you think of substantial form, you will be misunderstanding these concepts as badly as -- indeed, far worse than -- you would be misunderstanding molecules if you thought of them as literally being little balls held together by sticks, or of spacetime as if it were literally a kind if sheet with indentations in it.  Similarly, if you think of Descartes’ notion of res cogitans on the model of “ectoplasm,” or goo of the sort you’d see in Ghostbusters only invisible and intangible, or as “bits of non-clockwork” (as Gilbert Ryle described it), then you will be taking it to be nearly the opposite of what Descartes actually had in mind.  For these are all quasi-material kinds of thing insofar as they imply extension and/or composition.  And Descartes’ whole point was that a res cogitans is neither extended nor composed of parts.  It is precisely the sort of thing you cannot visualize, nor model on the workings of any kind of material system whatsoever, even the most ethereal.
My problem with pure actuality, substantial form, etc, is not that I misunderstand them through misleading attempts at visualisation, but that I can't attach any meaning to them at all.  My suspicion is that the philosophers who advance these ideas are trapped in Wittgenstein's language net.  They have been systematically misled by various maladaptations present in ordinary language.  This idea goes back at least to William of Ockham.  It's a very large and disparate philosophical research programme bits of which I but dimly make out.  Some of the posts on this blog hint in these directions.

Double standard 

And this is where so many New Atheist types come to grief.  (As I find I keep having to reassure the hypersensitive reader, no, I don’t mean all atheists.  I mean the kind of atheist who seriously thinks a Richard Dawkins, Jerry Coyne, or Laurence Krauss deserves to be mentioned in the same breath with J. L. Mackie, J. Howard Sobel, or Quentin Smith.)  Those among them who actually know something about science (and not merely how to shout “Science!”) are well aware that you are not going to understand physics properly if you take too seriously the mental images we tend to form when we hear terms like “spacetime,” “particle,” “energy,” and the like.  They are well aware that physics requires us to abstract from ordinary experience, to move away from what we can visualize or otherwise imagine.  The man on the street may think that whatever is real must be something you could in principle see, hear, touch, smell, or taste, but the more scientifically savvy sort of New Atheist knows that this is a vulgar prejudice, and that it is with the intellect rather than the senses that we truly understand the world.
But what do we find in quantum electrodynamics?  Feynman diagrams.  Pictures of the combinatorial possibilities involved in the interaction of two electrons, say,  and the electromagnetic field.
And yet, when dealing with metaphysical or theological concepts New Atheist types suddenly become complete Philistines, feigning an inability to grasp anything but the most crude and literal physical descriptions.  Hence if you claim that the human mind is immaterial, they suppose that you simply must be committed to the existence of a sort of magical goop that floats above the brain; and if you say that the universe has a cause they will insist that you must believe in a kind of super-Edison who draws up blueprints, gets out his tools, and sets to work.  And when you object to these preposterous straw men, they will pretend that they cannot understand your language in any other way, that it is mere empty verbiage unless read in such a crassly mundane fashion.  Of course, if they held physics to the same narrow, literalistic standard, they would have to dismiss wormholes, quantum foam, black holes, gravity wells, electric fields, centers of gravity, and on and on.  (I’ve discussed this double standard before, here and here.)
Well, perhaps there are two standards in operation.  The first is the standard applied to mathematical proof and the empirical testing of its physical interpretation.  The  second is the poetry of metaphysics.  But I will check out those earlier postings.
It is no good to object that the predictive and technological successes of physics justify this double standard, for two reasons.  First, the predictive and technological successes of physics are relevant only to the epistemic credentials of physics, but not to its intelligibility.  In other words, that such-and-such a theory in physics has been confirmed experimentally and/or had various practical applications is relevant to showing that it is correct, but it is not necessarily relevant to interpreting the content of the theory.  Physicists knew well enough what Einstein was claiming before tests like the 1919 and 1922 eclipse experiments provided evidence that he was right.  Similarly, though string theory has proved notoriously difficult to test, we know well enough what the theory means; the trouble is just finding out whether it’s true.  (No one would make the asinine claim that string theory simply must be committed to the existence of literal microscopic shoelaces unless and until some experimental test of the theory is devised.)   So, even if it were correct to say that metaphysical and theological claims cannot be rationally justified, it simply wouldn’t follow that such claims must be given the crude readings New Atheists often foist upon them, on pain of being empty verbiage.  But it is, in any case, not correct to say that they cannot be rationally justified, which brings us to the second problem.  That the methods of empirical science are rational does not entail that they are the only methods that are rational.  In particular, and as I have pointed out many times, it is simply a blatant non sequitur to claim that science’s success in discovering those aspects of reality that are susceptible of strict prediction and control shows that those aspects exhaust reality.  This is like a drunk’s insisting that because it is only under the streetlamp that there is light to look for his keys, it follows that the keys cannot be elsewhere and/or that there cannot be methods by which they might be sought elsewhere.
This is one of Ed's more opaque passages.  Has he finally ascended into the empyrean? Can anyone explain what he is getting at here?
As I have also pointed out many times, the premises from which the historically most important arguments for God’s existence proceed derive, not from natural science, but from metaphysics and the philosophy of nature.  They are, that is to say, premises that any possible natural science must take for granted, and are thus more secure than the claims of natural science, not less -- or so many natural theologians would claim. Obviously such claims are controversial, but the point is that to insist that metaphysical and theological assertions must be justified via the methods of natural science if they are to be worthy of attention is not to refute the metaphysician or theologian, but merely to beg the question against the metaphysician or theologian.  Philosophical arguments are different from empirical scientific arguments, but they are no less rational than empirical scientific arguments.
Metaphysical claims concerning the foundations of natural science are more secure than the claims of science itself, yet they are controversial?  Have I understood this?

Thinking abstractly 

Some readers might wonder how what I am saying here squares with what I said in a recent post about the danger of reifying abstractions.  But there is no inconsistency.  Naturally, I was not saying in the earlier post that abstraction per se is bad; indeed, I said the opposite.  What I was criticizing was treating as substances (in the Aristotelian sense of that term) things which of their nature cannot be substances.  Mathematical features of reality, for example, are aspects of substances and of relations between substances, rather than substances in their own right.  Hence it is an error to treat the mathematical description of nature that physics gives us as if it were a complete description.  Bodily organs like brains are also not substances but rather components of substances (namely of certain kinds of organisms) and intelligible only by reference to the complete organisms of which they form integral parts.  Hence it is a category mistake -- deriving from a tendency first to abstract the brain from the organism and then fallaciously to treat it as a substance in its own right -- to speak (as some neuroscientists and philosophers do) of the brain or its components as if they “see,” “interpret,” etc., or to conclude that since free choice, purpose, etc. are not to be found at the neurological level of description, it follows that they don’t exist at all.  These concepts apply in the first place only to the organism as a whole, and not to its parts. The arguments of natural theology that I am defending do not commit errors like this.  They abstract from experience, but they do not fallaciously treat accidents as if they were substances or parts as if they were wholes.
I agree with Ed here.  Loose talk of brains seeing and interpreting conflates the languages of the manifest and scientific images and results only in confusion.  Conversely, Ed should not seek to inject the terms of his preferred theory of the manifest image into the scientific image.
In any event, it is only by learning to think abstractly -- to engage in rational thought in its highest and purest form -- that you are ever going to understand metaphysical and theological arguments well enough to earn the right to criticize them.  “New Atheists” -- by which, again, I do not mean all atheists, but rather the likes of Dawkins, Coyne, Myers and their innumerable online clones -- have not earned this right, precisely because they do not think at this high level.  Indeed, they do very little thinking at all where metaphysics and theology are concerned, unless you count smartass remarks aimed at straw men followed by mutual high fives “thinking.”  When dealing with one of these brainiacs, you might as well meet him where he’s at and channel Biff Tannen: [insert video clip here]
So, after four thousand words, the upshot is that Dawkins et al are not worthy critics of Ed's Aristotelianism because their metaphysical thinking is stuck in the imagistic rather than the intellectual, and hence isn't really thinking at all.

You can't get there from here

Victor Reppert has a recent post loosely summarising a number of problems for physicalism, which has set me thinking.  Following my usual practice, I comment directly on gobbets of Victor's post.
1. Suppose we are given a complete list of physical facts, facts about where all the particles are. The information, thus given is insufficient to determine a unique mental state that a person is in. There is no entailment relation of any kind to the relevant mental state.
Indeed.   This, I believe, is known as the anomalism of the mental.   A physicalist has to offer some account of why this is so.  Here is a suggestion that I'd like to receive comments on.  I start with the thought that our only contact with the mental is through language, typically propositional attitude reports.  It's not as if we have an extra sense by which come to know the mental.  For example, our visual sense is equipped with qualities like colour and shape.  We can pay attention to these aspects without seeing any object, and sometimes these aspects cannot be made sense of as objects, and we are unable to describe a scene in propositional terms.  Example.  In contrast, the mental simply manifests itself in ready-made propositions, or rather, sentences.  Indeed, a number of writers have asked the question,  How can I tell what I think till I see what I say?  This sounds like Lewis Carroll's Alice but it is in fact EM Forster.  This suggests to me the following picture.

Sentences here count as physical.  Sentences 'in the head' can be uttered.  Brain states are clearly physical.  So we have a causal relation labelled language production.  We have little idea at the moment how language production works, but at least it relates the physical to the physical, so we can have some hope that the methods of science will uncover more.  How do mental states fit in?   We all seem to believe that there are such things as mental states and that they lead to the production of utterances, but it's not at all clear how the dotted horizontal arrow does its work.  One possibility is to think of mental states as theoretical entities introduced to explain sentences just as particles and fields are theoretical, ie, not directly sensed, entities brought in to explain matter.  The horizontal arrow then represents some set of theoretical principles by which sentences can be derived from mental states, much as physical principles enable us to derive the behaviour of ordinary bodies from that of their particles.  On this understanding it's hardly surprising that we can't specify the upward pointing dotted arrow, though it does make sense that mental states appear to supervene on the physical brain states.   How close is this to eliminativism?   Quite close, I guess.
2.  In virtue of what is some physical state about some other physical state? This is the familiar worry about intentionality, a worry made more difficult by my claim that the kind of intentional states involved in rational inference are states in which the content is understood by the agent and put into a propositional format.
I suspect the only sense in which physical state B can be said to be about physical state A is if A is causally contributory to B so that B contains some information about A.  This seems to rule out a physical basis for intentionality, for we can think about things that don't physically exist.  I'm inclined to explain the 'aboutness' of thoughts by means of the 'aboutness' of sentences.  Again, our contact with thoughts qua mental states is through the sentences they produce.  The aboutness of sentences is a shallow syntactical business by which sentences analyse into subject terms and predicate terms.  Is this eliminativism with respect to intentionality?  You tell me.  I certainly take issue with Victor's characterisation of inferential intentional states.  I think he has things backwards.  For me the 'mental content' manifests itself in propositional format, ie, sentences, and then becomes available to be understood.
3.  In the case of mental states, I do not see how the physical states can possibly “add up” to any determinate mental state. There is a qualitative difference between the physical base and mental content, that no amount of investigation can possibly overcome.
I agree.  But I don't get from the physical to the mental by a process of accumulation like building a brick wall (Victor's metaphor in his original post).  
4.  Given naturalism’s commitment to the natural sciences, the naturalist must presuppose the existence of mathematicians as well as scientists. Therefore, some serious consequences follow from the indeterminacy of mental states. It would mean that what Dawkins means by atheism is indeterminate. It means that it is not literally true that Einstein developed his theories of relativity from Maxwell’s equations.*
This follows a quote from Daniel Dennett arguing for the indeterminacy of mental states.  Victor feels that mental states must be determinate else rational thought be impossible.  I say that inference operates on sentences and sentences are quite determinate.  Have you ever repeated a sentence over and over in the hope that its implications become clear?   The meaning of a sentence may be indeterminate---ultimately the meaning of a sentence is what it does to us, the changes it produces in our brain state, and this is certainly indeterminable with current technology---but it is sentences that are the primary bearers of truth, in that it is sentences that we judge true or false.
5.  More to the point, brain processes, composed as they are of meaningless chemical components, seem as inherently devoid of intentionality as soundwaves or ink marks. Any intentionality they would also have to be derived from something else. But if anything physical would be devoid of intrinsic intentionality, whatever does have intrinsic intentionality would thereby have to be non-physical. Sine the mind is the source of the intentionality of physical entities like sentences and pictures, and doesn’t get its intentionality from anything else (there’s no one “using” our minds to convey meaning) it seems to follow that the mind has intrinsic intentionality, and thus is non-physical.
This is a quote from Ed Feser.  There is something deeply amiss with the notion of intentionality.  It splits the world into two disjoint classes, the interpreters and the interpreted, processor and data.  But brain states are clearly simultaneously both processor and data.  How are we to understand this? Shades of Frege's object versus concept distinction perhaps?

* Actually, it isn't true  that Einstein developed his theories of relativity from Maxwell’s equations.  Certainly not GR.  SR starts with the observed constancy of the speed of light and derives the Lorentz transformations.  Earlier work (check this!) had shown that Maxwell's equations are Lorentz invariant.

Feser on teleology

In the course of a 4000 word essay aimed squarely at the ignorance of Jerry Coyne,  Ed Feser gives us a discussion on teleology.
Consider the notion of “purpose.”  Coyne seems to think that all talk of purpose entails a conscious rational agent like us, but that is, conceptually speaking, just sloppy.  Where purpose is concerned -- a better term would be “teleology” or (better still because unassociated with irrelevant pop-theology baggage) the Scholastic’s term “finality” -- there are, as I have pointed out many times (e.g. here), at least five kinds, with each of the last four progressively more unlike the sort we know from introspection.  Hence we can distinguish:

1. The sorts of purposes we know from our own plans and actions.  In this case the end that is pursued is conceptualized.  When you order a steak, you conceptualize it as steak (as opposed, say, to vegetable protein processed to look and taste like steak), you express this concept linguistically by using the word “steak,” and so forth.

2. The sorts of purposes non-rational animals exhibit.  A dog, for example, exhibits a kind of purpose or goal-directedness when it excitedly makes its way over to the steak you’ve dropped on the floor.  Such a purpose is certainly conscious -- the dog will see the meat and imagine the appearance and taste of past bits of meat it has had, and it will also feel an urge to eat the meat -- but it is not conceptualized.  The dog doesn’t think of the meat as meat (as opposed to as textured vegetable protein), it doesn’t describe it using an abstract term like “meat,” etc.

3. The sorts of “purposes” plants exhibit.  A plant will grow “toward” the light, roots will “seek” water, an acorn “points to” the oak into which it will grow, etc.  These “purposes” are not only not conceptualized, but they are totally unconscious.  A plant will not only not think of the water it “seeks” as water (as a human being would), but it will not feel thirst or anything else as it “seeks” it (as an animal would).

4. The “goal-directedness” of complex inorganic processes.  David Oderberg offers the water cycle and the rock cycle as examples of a kind of inorganic “goal-directedness” insofar as there is an objective (rather than merely interest-relative) fact of the matter about whether certain occurrences are parts of these causal processes.  For instance, the formation of magma may both cause certain local birds to migrate and lead to the formation of igneous rock, but causing birds to migrate is no part of the rock cycle while the formation of igneous rock is part of it.  That each stage of the process “points” to certain further stages in a way it does not “point” to other things it may incidentally cause reflects an extremely rudimentary sort of teleology.  It is a kind of teleology or “directedness” that involves neither conceptualization of the end sought (as human purposes do), nor conscious awareness of the end (as animal purposes do), nor the flourishing of a living system (as the “purposes” of plants do).

5. Finally there is a kind of absolute bare minimum of “directedness” exhibited in even the simplest inorganic causal regularities.  As Aquinas argued, if A regularly generates some specific effect or range of effects B (rather than C, or D, or no effect at all), there is no way to make this intelligible unless we suppose that A is inherently “directed toward” or “points to” the generation of B (rather than to C, or D, or no effect at all).  Suppose all higher level causal regularities -- not only the water and rock cycles, but even simpler phenomena like the way the phosphorus in the head of a match generates flame and heat when the match is truck, or the way ice cools down room-temperature water surrounding it -- were entirely reducible to causation at the micro-structural level.  Still, we would have absolutely basic causal regularities -- the fact that some micro-structural phenomenon A regularly generates a range of outcomes B -- that is intelligible only if we suppose that A inherently points to B.  Or so the traditional Aristotelian view goes, anyway.  Here we lack in A not only conceptualization, consciousness, and life, but also complexity of the sort in view in teleology of Type 4.  There is just the bare “pointing to” or “directedness toward” B which would exist even if the causal transaction were not part of some larger structure.
What are we to make of this?  Can the single concept 'purpose', 'teleology', or 'finality' span such a vast range of phenomena described in (1) to (5)?  I struggle with this.  As, in a way, does Feser.  For as we move from (1) to (5) the concept seems to come under increasing stress, as evidenced by the frequency of the quotation marks.  One question I'd like to ask is this.  If everything has purpose(s), how do purposes interact?  Is my 1-purpose in going to the fridge somehow a sum or composition of the 5-purposes of my molecules?  Is this panpsychism? This query is analogous to the query directed to the Aristotelian theory of forms: How, if at all, is the form of a thing related to the forms of its parts?  Again, it would seem that we should say that the 5-purposes of molecules are trivially satisfied.  They are never thwarted.  But my 1-purpose in going to the fridge is easily thwarted.  How does it come about that some purposes can be thwarted?  Then again, perhaps the 5-purposes of molecules can be thwarted.  Maybe what happens in nature is the outcome of an argy-bargy of competing purposes among the molecules.  Perhaps a theory of composition for purposes could answer this question?

Let me say that I accept entirely Ed's 1-purposes, though I don't appreciate the emphasis he is making in his paragraph (1) above.  I would want to say that a purpose P in performing action A is a reason for A, in the sense that one believes that in some context C, P follows from A.   A suggestive notation might be C,A ⊢ P.   A purpose P for an object O is a reason for its existence:  C, ∃O ⊢ P, in an abuse of notation.  There is much that needs to be clarified here.  We are clearly in the realm of the rational planning of our actions in order to achieve our ends. The key idea is the notion of logical sufficiency.  Also, that a purpose is a cognitive entity, a thought, something that can participate in an inference, rather than a spatio-temporal entity or property.   It's difficult to see how to extend this idea to other domains.   I think Ed's 2, 3, 4, and 5-purposes must be metaphorical usages, and the metaphor is increasingly stretched as we go down the list.   I suggest that the sense of directedness or of finality that Ed finds is the sense in which the premises of an inference lead to its conclusion.  The spatial metaphors here are striking.  Let's consider his example of a match.  Suppose we have internalised our experience of matches into a general proposition: striking a match produces a flame.  So producing a flame might be our purpose or our end in striking a match.  Without any further explanatory resources at our disposal we might be tempted to account for the regularity expressed by the general proposition by means of a purpose or end or directedness towards producing a flame that is inherent in striking a match.  This might be seen as a vestige of animism.  The difficulties with it are immediately apparent.  Is the directedness inherent in the match or in its striking? As I understand it, the Aristotelian view is that these 'qualities' are inherent in the objects.  Certainly, causation is seen as a relation between objects. How then does the striking come into it?  The problem is that the resources available in a explanation of this kind---ordinary objects, or even ordinary objects equipped with directednesses---are too coarse-grained.  A nice demonstration of this is Ed's ice-cube example.  Granted that the ice-cube at minus five degrees Celsius, say, will cool liquid water at twenty degrees.  But it will also warm liquid CO2, say, at minus sixty Celsius.
For as I have also pointed out many times (e.g., once again, here) there are several possible views one could take about purported teleology or finality of any or all of the five sorts just described:

A. One could hold that one or more of the kinds of teleology described above really do exist but that it is in no way inherent in the natural world, but rather imposed on it from outside by God in something like the way the purposes of an artifact are imposed on natural materials by us.  Just as the metal bits that make up a watch in no way have any time-telling function inherent in them but derive it entirely from the watchmaker and users of the watch, so too is the world utterly devoid of teleology except insofar as God imparts purposes to it.  This “extrinsic” view of teleology is essentially the view represented by William Paley’s “design argument.”

B. One could hold instead that teleology of one or more of the kinds described above really does exist and is inherent in the natural world rather than in any way imposed from outside.  Someone who takes this view might hold (for example) that an acorn really does have an inherent and irreducible “directedness” toward becoming an oak, or that in general efficient causes really are inherently “directed toward” or “point to” their effects, and that this just follows from their natures rather than from any external, divine directing activity.  Why does an acorn “point toward” becoming an oak?  Not, on this view, because God so directs it, but just because that is part of what it is to be an acorn.  This ”intrinsic” view of teleology is the one usually attributed to Aristotle (who, though he affirmed the existence of a divine Unmoved Mover, did not do so on teleological grounds, as least as usually interpreted).

C. One could hold that teleology of one or more of the kinds described above really does exist and has its proximal ground in the natures of things but its distal ground in divine directing activity.  On this view (to stick with the acorn example -- an example nothing rides on, by the way, but is just an illustration) the acorn “points to” becoming an oak by its very nature, and this nature is something that can be known whether or not one affirms the existence of God.  To that extent this view agrees with View B.  But a complete explanation of things and their natures would, on this View C, require recourse to a divine sustaining cause.  This is the view represented by Aquinas’s Fifth Way, which (as I have noted many times) has nothing whatsoever to do either with Paley’s feeble “design argument” or with the arguments of recent “Intelligent Design” theorists.  (I have expounded and defended Aquinas’s Fifth Way in several places, such as in my book Aquinas and in greatest detail in a recent Nova et Vetera article.)

D. One could hold that one or more of the kinds of teleology described above are in some sense real but only insofar as they are entirely reducible to non-teleological phenomena.  To speak of something’s “pointing to” or being “directed toward” some end is on this view “really” just a shorthand for some description that makes no reference whatsoever to teleology or finality.

E. Finally, one could hold that none of the sorts of teleology described above exists in any sense, not even when understood in a reductionist way.  They are entirely illusory.
My view is closest to (E).  1-purposes exist, though they are cognitive entities. 2, 3, 4, and 5-purposes do not.
1. Now that means that of the approaches to teleology or finality described above, the materialist is committed to either View D or View E.  But View D really collapses into View E.  For attempts to reduce teleological notions to non-teleological notions are notoriously problematic.  To take a stock example, suppose it is claimed that such-and-such a neural structure in frogs serves the function or purpose of allowing them to catch flies (insofar as it underlies frogs’ behavior of snapping their tongues at flies).  And suppose it is claimed that this teleological description can be translated without remainder into a description that makes use of no teleological notions.  For instance, it might be held that to say that the neural structure in question serves that function is just shorthand for saying that it causes frogs to snap their tongues at flies; or perhaps that it is shorthand for saying that the structure was hardwired into frogs by natural selection because it caused them to snap their tongues at flies.  The trouble is that the same neural structure will cause a frog to snap its tongue at lots of other things too -- at BB’s, black spots projected onto a screen, etc. -- yet it would be false to say that the function of the structure in question is the disjunctive one of getting frogs to eat either flies or BBs or spots on a screen, etc.   Of course, someone might respond: “But that’s because the reason the neural structure gets frogs to snap their tongues, and the reason it was favored by natural selection, was in order to get them to eat flies, not to eat BB’s or spots on a screen!”  But that’s just the point.  To say that “the reason” the structure exists is “in order to” get frogs to do that, specifically, is to bring teleological notions back into the analysis, when the whole point was to get rid of them.
Ed is being a little careless here.  The underlined sentence conflates two reasons:
a. Why the neural structure gets frogs to snap their tongues, and
b. Why the neural structure was favoured by evolution.
The explanation for (a) is in terms of the physiology of frogs---how the neural structure processes retinal images of small dark objects and stimulates the muscles of the tongue.  The explanation for (b) is the usual Darwinian one---the differential reproduction of frogs equipped with such neural structures and refinements thereof, compared to those without.  One can explain this without resort to 'in order to'.  I'm afraid Ed is putting up an all-to-familiar anti-Darwinian straw-man.
2. This sort of problem -- known by philosophers as the “disjunction problem” -- illustrates the impossibility of trying to reduce teleological descriptions to non-teleological ones.  Such purported reductions invariably either simply fail to capture the teleological notions, or they smuggle them in again through the back door and thus don’t really reduce them after all.  Hence, as naturalists as otherwise different as John Searle and Alex Rosenberg have acknowledged, a consistent materialist has at the end of the day to deny that teleology really exists at all.  That is to say, he has to opt for what I have labeled View E.
I fail to see the relevance of the disjunction problem.  This is supposed to show that there can be no unique function or purpose for a physiological structure.  Under my interpretation of 'purpose' this is obvious.  One would not expect there to be a unique P such that C,∃O ⊢ P.  But this has no impact at all on the Darwinian argument.  Among the things in the frog's environment that trigger tongue snapping are flies, and the benefits of snapping at nutritious flies outweigh, in terms of reproductive success, the downsides of snapping at possibly-noxious fly-like things.  This account need not mention functions or purposes.  Isn't Jerry Fodor's attack on Darwinism just this misapplication of the disjunction problem? Ed has not shown that Darwinism must be formulated in teleological terms, nor does this argument rule out my modified (E) view.
3. Now this is where an insuperable problem for materialism comes in.  If you take View E, then you have to say that teleology, purpose, “directedness” or “pointing toward” of any kind is an illusion.  But illusions are themselves instances of “directedness” or “pointing toward.”  In particular they are instances of intentionality, where intentionality is what the “directedness” or “pointing toward” that is definitive of teleology in general looks like in the case of mental states (thoughts, perceptions, volitions, and the like) in particular.  This is why the intentionality of the mental has notoriously been difficult for the materialist to account for.  For materialism maintains that there is no irreducible “directedness” in the world, yet intentionality just is a kind of “directedness.”  A thought or perception is about or directed at a state of affairs (whether real or illusory), a volition is about or directed at a certain outcome (whether actually realizable or not), and so forth.
Ed now assimilates intentionality to purpose, via what amounts to a pun on 'directedness'.  The sense of directedness in intentionality is not the sense of entailment that I claim for purposiveness.  The directedness of intentional states is a quasi-relation between thoughts and objects.  The directedness of purposiveness, or so I claim, is the entailment relation between thoughts.  So a denial of purposiveness in the material realm need not rule out the intentionality of the mental realm, even if the former provides the material substrate of the latter.  The difficulty for materialism of accounting for intentionality is not due to the lack of purposiveness in the material realm.
4. As materialists like Alex Rosenberg and Paul Churchland see, this is why a consistent materialist really has to be an eliminativist and deny the reality of intentionality altogether.  The problem is that this simply cannot coherently be done.  To be sure, the eliminativist can avoid saying blatantly self-contradictory things like “I believe there are no beliefs,” but that doesn’t solve the basic problem.  For he will inevitably have to make use of a notion like “illusion,” “error,” “falsehood,” or the like even just to express what it is he is denying the existence of, and these notions are thoroughly intentional (in the sense of being instances of intentionality).  For one to be in thrall to an “illusion” or an “error” just is to be in a state with meaning, with directedness on to a certain content, and so forth.  In short, to dismiss the “directedness” or “pointing toward” characteristic of teleology and intentionality as an illusion is incoherent, since illusions are themselves instances of the very phenomenon whose existence is being denied.  We saw in a recent series of posts how Rosenberg tries to solve this incoherence problem -- in an attempt that is, to his credit, more serious than that of other eliminativists -- but fails utterly.
I wouldn't want to deny intentionality, though I don't think it's all it's cracked up to be.  It's not at all clear to me that intentionality is captured through this notion of 'directedness'.  It's only through his conflation of the apparent directedness of intentionality with the hypothetical directedness of teleology that Ed thinks that the denier of teleology must deny intentionality.  And that's down to a rather bad pun.