Friday, September 26, 2008

Some brief arguments for dualism, Part II

Following Aristotle, the Scholastic tradition famously held that final causes – goal-directedness, purposiveness, natural ends – permeate the natural world. Contrary to a popular misconception, this does not mean that they thought that everything in the world has a purpose or function in the sense that biological organs have purposes or functions. Hence it is no good to accuse them of thinking, absurdly, that piles of dirt, asteroids, mountain ranges, and the like simply must play some role within the universe as a whole that is somehow analogous to the role hearts and kidneys play in the body. Functions like the kind bodily organs play constitute only one, relatively rare, kind of final causality. Nor did they think that final causality is generally associated with anything like consciousness. For an Aristotelian to say that a plant by virtue of its nature “wants” to grow is just a figure of speech. Literally speaking the plant does not, of course, want anything at all, since it is totally unconscious. It is only in us, and in certain other animals, that final causes are associated with conscious awareness.

What the Scholastics did have in mind is summed up in Aquinas’s dictum that “every agent acts for an end,” otherwise known as the “principle of finality.” By an “agent” he means that which brings about or causes some effect. And what he is saying is that when a certain cause generates a certain effect or range of effects in a law-like way (as we would say today) that is only because it naturally “points to“ or is “directed towards” that effect or range of effects as its proper end. For example, a match when struck will, unless prevented (e.g. by being water damaged), generate flame and heat – and flame and heat specifically rather than frost and cold, or the smell of lilacs, or no effect at all. It has an inherent causal power to bring about that effect specifically. What Aquinas and the other Scholastics argued is that unless we acknowledge the existence of such inherent powers, unless we recognize that whenever a certain efficient cause A generates its effect B that is only because the generation of B is the final cause or natural end of A, then we have no way of making intelligible why it is exactly that A generates B specifically rather than some other effect or no effect at all. The existence of final causes is, in this sense, a necessary condition for the existence of efficient causes – of, that is to say, causation as modern philosophers tend to understand it. This is one reason Aquinas held the final cause to be “the cause of causes.”

Now modern philosophy, and in particular modern philosophy’s conception of science, is defined more than anything else by its rejection of final causes. Indeed, as philosophers like William Hasker and David Hull have pointed out, at this point in the history of science, what remains of the “mechanistic” picture of the natural world which we have inherited from the early moderns is really nothing but this rejection. As I argue in The Last Superstition, there has never really been any serious philosophical case for this rejection; it was, and still is, more ideologically than intellectually motivated. Moreover, there are in my view (and, again, as I argue in TLS) overwhelming reasons to think it was a mistake. One of them is that, as Hume’s famous puzzles illustrate, causation has indeed become seriously problematic in modern philosophy in exactly the way Aquinas’s analysis would lead us to expect it to, given the abandonment of final causes.

The abandonment of final causes has also crucially contributed to the creation of the “mind-body problem,” something that did not exist, certainly not in anything like the form familiar to contemporary philosophers, prior to the moderns’ rejection of the Aristotelian-Scholastic metaphysical framework. For to insist that the material world is utterly devoid of final causes – devoid, that is to say, of anything that inherently “points to” or is “directed toward” anything beyond itself – is implicitly to deny that intentionality could possibly be material, for intentionality, of course, is just the mind’s capacity to point to or be directed towards something beyond itself, as it does in thought. (See my previous post in this series.) Hence to insist that the material world is devoid of any inherent final causes while at the same time acknowledging the existence of intentionality is implicitly to commit oneself to dualism. Indeed, this is surely one reason why Descartes, one of the fathers of the “mechanistic” revolution in science, was a dualist. Far from being a kind of pre-scientific holdover, dualism of the broadly Cartesian sort is a logical consequence of the turn to mechanism that defined the scientific revolution.

The only way to hold on to the mechanistic conception of nature while rejecting dualism is thus to deny the existence of intentionality. And that is why, as John Searle has argued, all extant forms of materialism do indeed implicitly deny its existence, and thus (I would say) amount to disguised forms of eliminative materialism. This is halfway admitted by Jerry Fodor when he writes, as he does in Psychosemantics, that “if aboutness [i.e. intentionality] is real, it must be really something else.” That is to say, intentionality per se simply cannot be real given the mechanistic conception of the material world that Fodor, like all materialists, has inherited from the early modern philosophers. Hence the most the materialist can do is try to substitute for it some physicalistically “respectable” ersatz. But this is simply eliminative materialism in “folk psychological” drag; and eliminative materialism, however you dress it up, is simply incoherent. (Yet again, see TLS, and in particular chapter 6, for the details.)

We have, then, another brief argument for dualism, which can be summarized as follows: If materialism is true, then (given that it is committed to a mechanistic conception of the material world), there are no final causes, and thus nothing that inherently “points to” or is “directed at” anything beyond itself; and in that case, there can be no such thing as intentionality; but there is such a thing as intentionality; therefore materialism is not true.

This is an argument for dualism, I should say, at least if one admits that the material world exists in the first place (which, of course, everyone other than a few adherents of idealism would admit), because it implies that there are features of the world other than its material features. The only way to avoid the dualistic consequences (other than opting for eliminativism or idealism) would be to acknowledge that the Aristotelians were right after all, and that final causes are a real feature of material reality. But that would, of course, be to abandon the entire modern mechanistic-cum-materialistic interpretation of science. Nor would it really stave off dualism for long, for it would simply open the door to the Thomistic or hylemorphic (as opposed to Cartesian) version of dualism. But that is a story for another time – a story which, like other details of the argument sketched here, can be found (if I might be forgiven one more shameless plug) in The Last Superstition.


  1. Hi Professor Feser, another excellent post!

    I'm a dualist. But I admite that dualism (like materialism) have some problems.

    The most frequently objection is the "interactionism problem". How to connect an inmaterial substance (soul/mind) with a material brain?

    Another objection is that dualism violates the law of conservation of energy, because it implies a causal energy of the soul to move matter. I'm not sure about the force of that objection, because in quantum mechanics have been experimentally verified the violation of conservation of energy:

    Another objection is that dualism, as a hypothesis, isn't falsifiable. In my opinion, that objection isn't correct, because dualism is a philosophical hypothesis, not a scientific one. And the popperian falsiability isn't a criterium for a philosophical position, but only of scientific hypothesis.

    But materialism have many problems too. For example, philosopher William Lycan (a materialist) wrote: Though the arguments for dualism do (indeed) fail, so do the arguments for materialism. And the standard objections to dualism are not very convincing; if one really manages to be a dualist in the first place, one should not be much impressed by them. My purpose in this paper is to hold my own feet to the fire and admit that I do not proportion my belief to the evidence

    Also, materialism haven't explained the problem of "qualia" or the "hard problem of consciousness". In fact, in some cases, materialists have explained it away (e.g. as seen in eliminative materialists)

    It seems that many materialists accept materialism as a default (and unexamined) position.


    Professor Feser, I have a doubt: does all the mental states have intentionality? Or only some of them have it? I'm thinking in pains and nausea as examples of feelings without a clear "aboutness"

  2. Hi ZC, I'm sympathetic to the view that even the sorts of mental states you refer to have a kind of intentionality. E.g. pain is arguably "directed towards" the part of the body in which the pain is felt. Tim Crane has defended this view at length (e.g. in his book Elements of Mind) and I say a little about it in my book Philosophy of Mind.

    Re: the interaction problem, I think I'll address that in a post within a day or so.

  3. Another argument to the same end is that the via moderna, at its heart, thinks all knowledge is sense knowledge- and all the rest follows.

    They abandoned final causes because they abandoned causes; they lost causes because they could not see how two things (cause and effect) could form one (this is the real heart of Hume. His claim is the same as Democritus's), but they lost this because they identified intellect with sensation.

    Without a power of intellect as opposed to sensation, potency becomes impossible to know (we cannot sense potency). But in losing this, we lose Aristotle's only way of making one thing out of two. Even _phyical_ interaction becomes impossible, still less mind body interaction. No causality at all. As an added anti-bonus, now that our mind is seen as a sense power, it corrupts with death.

  4. Hello thomism, I agree completely.