Accept no imitations

Given that he’s just become a movie star, Alan Turing’s classic paper “Computing Machinery and Intelligence” seems an apt topic for a blog post.  It is in this paper that Turing sets out his famous “Imitation Game,” which has since come to be known as the Turing Test.  The basic idea is as follows: Suppose a human interrogator converses via a keyboard and monitor with two participants, one a human being and one a machine, each of whom is in a different room.  The interrogator’s job is to figure out which is which.  Could the machine be programmed in such a way that the interrogator could not determine from the conversation which is the human being and which the machine?  Turing proposed this as a useful stand-in for the question “Can machines think?”  And in his view, a “Yes” answer to the former question is as good as a “Yes” answer to the latter.

Aristotle’s four causes versus pantheism

For the Platonist, the essences or natures of the things of our experience are not in the things themselves, but exist in the Platonic “third realm.”  The essence or nature of a tree, for example, is not to be looked for in the tree itself, but in the Form of Tree; the essence of a man is not to be looked for in any human being but rather in the Form of Man; and so forth.  Now, if the essence of being a tree (treeness, if you will) is not to be found in a tree, nor the essence of being a man (humanness) in a man, then it is hard to see how what we ordinarily call a tree really exists as a tree, or how what we call a man really exists as a man.  Indeed, the trees and men we see are said by Plato merely imperfectly to “resemble” something else, namely the Forms.  So, what we call a tree seems at the end of the day to be no more genuinely tree-like than a statue or mirror image of a tree is; what we call a man seems no more genuinely human than a statue or mirror image of a man is; and so forth.

Vallicella on hylemorphic dualism

Hylemorphic dualism is the approach to the mind-body problem taken by Aquinas and the Thomist tradition more generally.  (The label may have been coined by David Oderberg, who defends the view in an important paper and in his book Real Essentialism.  “Hylemorphic” is sometimes spelled “hylomorphic,” though the former spelling is arguably preferable since it is closer to the Greek root hyle.)  The view holds both that the soul is the substantial form of the living human body (that is the “hylemorphic” part) and that it is unique among the forms of material things in being subsistent, that is, capable of surviving beyond the death of the body (that is the “dualism” part).  Our friend Bill Vallicella has recently put forward the following criticism of the view:

Vallicella on hylemorphic dualism, Part II

Bill Vallicella has kindly replied to my response to his recent post on hylemorphic dualism.  The reader will recall that Bill had suggested in his original post that, given the apparent tension between hylemorphism and dualism, Aquinas’s hylemorphic dualism seems ad hoc and motivated by Christian theological concerns rather than by philosophical considerations.  I argued that this charge cannot be sustained.  Whether or not one ultimately accepts hylemorphic dualism, if one agrees that there are serious arguments both for hylemorphism and for dualism, then -- especially when we add independent metaphysical considerations such as the Scholastic principle that the way a thing acts reflects the manner in which it exists -- one should at least acknowledge that hylemorphic dualism has a philosophical rationale independent of any Christian theological concerns.  It seems Bill still disagrees, but I do not see how his latest post gives any support to his original charge.

Causality, pantheism, and deism

Agere sequitur esse (“action follows being” or “activity follows existence”) is a basic principle of Scholastic metaphysics.  The idea is that the way a thing acts or behaves reflects what it is.  But suppose that a thing doesn’t truly act or behave at all.  Would it not follow, given the principle in question, that it does not truly exist?  That would be too quick.  After all, a thing might be capable of acting even if it is not in fact doing so.  (For example, you are capable of leaving this page and reading some other website instead, even if you do not in fact do so.)  That would seem enough to ensure existence.  A thing could hardly be said to have a capacity if it didn’t exist.  But suppose something lacks even the capacity for acting or behaving.  Would it not follow in that case that it does not truly exist?

Searle, Aquinas, and property dualism

In an addendum to his article “Why I Am Not a Property Dualist,” John Searle suggests that property dualism really entails substance dualism. For it describes mental properties as “arising from” and existing “over and above” the brain, and “these metaphors suggest that… consciousness is something separate from the brain” given that “uncontroversial properties of the brain, like weight, shape, colour, solidity, etc.” are not said to exist in that way. For consciousness to exist “over and above” the brain requires that it be “a separate thing, object, or non-property type of entity.”

Searle’s claim here seems reminiscent in some ways of Aquinas’s argument for the subsistence of the human soul at Summa Theologiae I.75.2:

Therefore the intellectual principle which we call the mind or the intellect has an operation "per se" apart from the body. Now only that which subsists can have an operation "per se." For nothing can operate but what is actual: for which reason we do not say that heat imparts heat, but that what is hot gives heat. We must conclude, therefore, that the human soul, which is called the intellect or the mind, is something incorporeal and subsistent.

Aquinas has argued earlier for the first claim made in this passage, viz. that intellectual operations do not involve a bodily organ. What he saying here is that this claim entails that that which carries out these operations, the human soul, must “subsist” apart from the body; it isn’t a mere accident or attribute of the body. The reason is the Scholastic principle that agere sequitur esse, activity follows upon being. Heat, as a mere accident or attribute, cannot cause something to be hot; rather it is the substance which has the heat that causes something else to be hot. Similarly, an operation which is not carried out by any bodily organ but which – qua operation rather than substance – cannot exist apart from some substance or other, must inhere in something immaterial.

So, when Searle tells us that immaterial mental properties would have to inhere in something immaterial rather than in a material object like the brain, he is saying something which seems to dovetail with Aquinas’s argument.

Still, things are a bit more complicated than that. For one thing, unlike many contemporary property dualists, Aquinas does not regard consciousness (as contemporary philosophers tend to understand “consciousness”) as immaterial. Rather, it is intellectual activity (grasping abstract concepts, reasoning, etc.) that he takes to be immaterial. Second, Aquinas is not only not a property dualist, he is not (contrary to appearances) a substance dualist either, certainly not in the way that sort of view has been understood since Descartes. Rather, he is a hylemorphic dualist. From a Thomistic point of view, substance dualism, property dualism, materialism, idealism, neutral monism, and all other post-Cartesian theories of the mind presuppose a mistaken and muddleheaded conception of both mind and matter – a conception which (among other things) makes it very difficult for contemporary philosophers even to understand the Thomistic view. As when dealing with Aquinas’s position on other specific philosophical questions, the only way properly to understand what he says about the relationship between mind and body is to situate it within his general metaphysics, which presupposes an understanding of the notions of act and potency, form and matter, substance and accident, essence and existence, analogical predication, etc. I set all this out in Aquinas, with chapter 4 devoted to Aquinas’s psychology and how it differs radically from contemporary substance dualism, property dualism, etc.

Now, some further reading, while you wait for your copy of Aquinas to arrive: First, my essay “Why Searle Is a Property Dualist,” which explains why Searle’s own anti-materialist arguments in philosophy of mind do in fact entail property dualism, despite his attempt to avoid this result. Second, check out David Oderberg’s article “Hylemorphic Dualism” for an overview of the Thomistic position. Third, take a look at Alfred Freddoso’s article “Good News, Your Soul Hasn’t Died Quite Yet” for a discussion of some of the differences between the Thomistic view and the standard modern ones (and why Catholics, especially, should be wary of the latter, including modern versions of dualism).

Supervenience on the hands of an angry God

In his book Physicalism, or Something Near Enough, Jaegwon Kim puts forward the following characterization of the materialist supervenience thesis:

I take supervenience as an ontological thesis involving the idea of dependence – a sense of dependence that justifies saying that a mental property is instantiated in a given organism at a time because, or in virtue of the fact that, one of its physical “base” properties is instantiated by the organism at that time.  Supervenience, therefore, is not a mere claim of covariation between mental and physical properties; it includes a claim of existential dependence of the mental on the physical. (p. 34)

Stroud on Hume

David Hume, as I often argue, is overrated.  But that’s not his fault.  It’s the fault of those who do the overrating.  So, rather than beat up on him (as I have done recently), let’s beat up on them for a change.  Or rather, let’s watch Barry Stroud do it, in a way that is far more genteel than I’m inclined to.

Animal souls, Part I

Here’s a postscript, in two parts, to my recent critique in Public Discourse of David Bentley Hart’s case for there being animals in heaven.  In this first part, I discuss in more detail than I did in the original article Donald Davidson’s arguments for denying that animals can think or reason in the strict sense.  (This material was originally supposed to appear in the Public Discourse article, but the article was overlong and it had to be removed.)  In the second part, I will address some of the response to the Public Discourse article.  Needless to say, those who haven’t yet read the Public Discourse article are urged to do so before reading what follows, since what I have to say here presupposes what I said there.