As my previous post made clear, the crucial question is whether anything like the teleological conception of nature that the traditional natural law theory rested on is plausible. Herzog seems to assume that a thoroughgoing mechanistic non-teleological view is just obviously correct, unproblematic, and uncontroversial. That is not so.

A standard way to understand the mechanistic revolution in natural science is as follows. Aristotelian science took material objects and processes to have substantial forms and objective ends or purposes, and regarded the qualities they exhibit to us in perception as inherent in the things themselves. Early modern science made the crucial moves of rejecting forms and objective purposes as explanatorily useless, and also of defining physical properties in a way that ignored sensory qualities, which were relegated to the mind. Thus temperature, for example, gets defined in terms of molecular motion, and the felt qualities of heat and cold are reinterpreted as inhering not in hot and cold things themselves, but in the subjective consciousness of the perceiver. Needless to say, this model inaugurated a powerful new approach to inquiry which has produced scientific theories of great depth and explanatory power. But it also opened up a deep metaphysical quandary known to philosophers as the mind-body problem.

As Thomas Nagel has pointed out, given that the explanatory method of modern science has involved carving off the subjective, first-person element of a phenomenon to be explained – that is, the sensory qualities objects present to us in experience (also known as “qualia”) – and redefining that phenomenon in objective, third-person terms, there is no way in principle that the application of this model can be extended to an explanation of the subjective, first-person realm of the mind itself. You cannot carve off the subjective, first-person element in this case precisely because the phenomenon to be explained just is the subjective, first-person element.

What is true of sensory qualities is no less true of natural functions and forms. Living things always posed a more serious challenge to the mechanistic ambition than did temperature and the like. If anything has an obvious natural end or clearly participates in a form, it would seem that organs and organisms do. But Darwinism showed, or seemed to anyway, that natural ends and purposes could be eliminated entirely from an account of nature, and that there were no fixed species that could correspond to forms as traditionally conceived. The purposes and forms that things seem to exhibit are on this view really only projections of the mind, and don’t exist objectively. But of course the act of projection itself, and intentionality in general, involve a directedness toward an object no less than natural functions and ends do. So whether or not such directedness really exists in the external world, it remains there in the internal world of the mind, with nowhere left to be shunted off to.

In short, the mechanistic model has succeeded only by sweeping everything that doesn’t fit the model under the rug of the mind. But there these phenomena remain, forming a considerable lump that cannot, in principle, be removed by further sweeping. This is why the mind-body problem has been so intractable. Contemporary materialistic philosophers are intent on applying the mechanistic model to the mind itself, their justification being that since it has worked so well everywhere else, it is bound to work well in this case too. But in doing so they forget that the only reason it has worked everywhere else is precisely that it has been able to relocate recalcitrant non-mechanistic phenomena into the mind. Predictably, then, materialist theories of the mind essentially just ignore what is essential to the mind and change the subject by talking about causal relations, counterfactual conditions, or something similarly irrelevant. They are implicitly eliminativist when they aren’t explicitly so. Hence philosophers like Jerry Fodor saying things like “If ‘aboutness’ [i.e. intentionality] is real, it must be really something else.”

This is by no means a problem recognized only by philosophers of a religious bent. Thinkers like Saul Kripke, Frank Jackson, Thomas Nagel, John Searle, David Chalmers, Colin McGinn, Galen Strawson, Michael Lockwood, Hilary Putnam, John McDowell, and many others have in their various ways raised challenges to the current materialist orthodoxy that derive in one way or another from the basic picture just outlined. Needless to say, none of these people is exactly a member of the so-called “Christian Right.” Most of them are not dualists of any sort and none of them is a Cartesian dualist. It must also be kept in mind that the popularity of materialism among philosophers of mind is a very recent phenomenon, going back not much further than the 1960s. Bertrand Russell changed his views many times throughout his long life, but he was never a materialist. Karl Popper was no theist, but he was a dualist. C.D. Broad, despite his atheism, thought that at least temporary survival of death might be possible, convinced as he was that the mind is partly non-physical. None of these philosophers was motivated by theological considerations or ignorant of science. They simply accepted what has, for purely philosophical reasons, traditionally been the mainstream view in philosophy about these issues: that mind and matter are like apples and oranges, the former being irreducible to the latter.

Obviously this is a very large topic, and there is no way I can deal with it in any detail here. I do so in my forthcoming book The Philosophy of Mind: A Short Introduction, where, rest assured, I not only discuss dualism and the traditional and contemporary objections to materialism and mechanism (in greater depth than the superficial and caricature-laden treatments afforded in so many introductory texts) but also make clear the reasons why materialism and mechanism have, quite understandably, been regarded as so powerful and intellectually compelling. My own position is a dualist one, but I recognize that the standard Cartesian form of dualism has serious problems, particularly in regards to its picture of mental causation and its account of the nature of immaterial substance. The source of these problems, though, is in my view that Cartesian dualism has essentially the same conception of matter and causation that mechanism and materialism do – indeed, Descartes himself was one of the inventors of this conception.

Whatever the truth of these matters, though, it suffices to note here that mechanism is by no means a philosophically unproblematic presupposition that moral philosophers can take for granted, and on the basis of which they may safely conclude that traditional natural law theory hasn’t a metaphysical leg to stand on. However the centuries-old problems I’ve described ultimately get worked out, it is not at all obvious that the right answer will be one that thoroughly vindicates the materialistic and mechanistic prejudices of contemporary philosophers. Mechanistic processes may well turn out to be merely one component, however pervasive, in a broader context that is irreducibly teleological. Those who assume this is impossible should keep in mind just how radically, and how quickly, philosophical orthodoxies can shift. British idealism and logical positivism are merely two examples of how positions that seem inevitable to one generation can come to seem preposterous to the next.

My own view, for what it is worth, is that the right way to understand the mind-body relationship is in terms of the hylomorphism of Aristotle and Aquinas. The soul is the form of the body, and it is in terms of formal causation, rather than efficient causation, that mind-body interaction must be understood. The mind-body problem as it exists today is more or less an artifact of the early modern philosophers’ abandonment of these traditional philosophical notions. What Alasdair MacIntyre said about ethics is true of metaphysics as well: the moderns have been playing with concepts that have no coherent meaning outside the ancient framework within which they first developed, and they have as a result been led into intractable problems that can be remedied only by a return to some version, albeit updated, of a classical philosophical worldview. This entails a kind of “Thomistic dualism” or “hylomorphic dualism” in the philosophy of mind. And it indicates that that it is to the work of “analytical Thomists” like Anscombe, Geach, Kenny, John J. Haldane, James F. Ross, David Oderberg and many others that we should look for ways to combine the genuine insights of modern analytic philosophy with a more traditional, and more adequate, metaphysics and ethics.

All of that is, I realize, programmatic at best. And what I’ve said thus far shows only that universal mechanism has not in fact been established; so far a positive defense of teleology hasn’t been offered. Notice, though, that if a Thomistic version of dualism can indeed be defended today – as some of the authors just mentioned believe, as do several other contemporary philosophers of mind and philosophers of religion – then that would by itself provide powerful support for the presupposition of traditional natural law theory that a human being participates in a form that determines his nature. Moreover, realism about forms and other abstract objects is hardly without prominent defenders in the mainstream of contemporary analytic metaphysics. It is silly, then, to pretend that materialism and mechanism have been established in general metaphysics any more than they have in the philosophy of mind – in which case it is, again, silly for moral philosophers to pretend that there is no longer any question of whether the metaphysical presuppositions of traditional natural law theory might be defensible.

And then there is the renaissance of rigorous argumentation in support of the traditional philosophical arguments for the existence of God, about which I have recently written elsewhere. Which brings me to the next point. How might an appeal to natural purposes and functions – the notion most centrally at issue in the debate over the traditional sort of natural law reasoning I described in my last post – be defended today? It seems to me that there are three broad approaches one could think to take: an appeal to immanent purposes, to divine purposes, or to what I will call naturalized or quasi-purposes. Let’s look at each in turn.

1. Immanent purposes: By “immanent purposes” I have in mind the old Aristotelian idea that all things in nature, including inanimate objects, in some sense have inherent natural ends or tendencies. Now whatever one thinks of this notion, it is important that one’s opinion be based on a correct understanding of it. Alluding to it in his recent post, Herzog says that “a friend of mine likes to say, ‘the sun is trying to come out from behind the clouds.’ Well, no, it isn’t.” Indeed it isn’t, but then, Aristotelians never said it was, at least not in the sense Herzog and his friend appear to assume. The idea wasn’t that the sun or the planets are consciously “trying” to do anything. It would be more accurate to think in terms of the aforementioned concept of intentionality, and intentionality is something all sorts of inanimate objects obviously have – for example, the sentences you’re reading right now. Sentences (or, strictly speaking, sentence tokens) despite their being mere squiggles of ink, say, or patterns of light on a computer screen, refer to or “aim at” something beyond themselves: objects, states of affairs, and so forth. All of us know this, and no one is inclined to make cheap jokes at the expense of someone who points it out (“Ha ha, he thinks sentences are trying to talk to us!”) But the Aristotelians were not necessarily saying anything any sillier than this. Their claim can be understood as the claim that planets, the sun, and so forth have a kind of intentionality: a directedness toward an end.

Now of course, sentence tokens do not have their intentionality inherently; by themselves they are just meaningless ink squiggles, or light patterns, or whatever, and get whatever intentionality they have from us. As John Searle would put it, they have “derived intentionality” rather than “intrinsic intentionality.” And the sun and planets would also seem, intuitively, devoid of any intrinsic intentionality. Indeed, it seems to me that that’s precisely why Aquinas, in the Fifth Way, argued that natural objects and processes could not have the intentionality they have if there were no divine mind directing them. He was making a point exactly parallel to the Searlean point that sentence tokens and other physical symbols could not have the intentionality they have apart from a mind that gives it to them.

For this reason, it seems to me that an appeal to immanent purposes is not the most promising avenue for a defender of traditional natural law to take. If he is going to have to appeal to God eventually anyway in order to make sense of the purposes he says exist in nature, he might as well just do it from the get go. That does not mean that there is no importance to the question of whether there might be a sense in which natural purposes are there in nature independently of God’s action; far from it. The question of what precisely is the nature of God’s causal influence on the world – the debate over secondary causes and occasionalism – is central to the metaphysics of theism. But since, where ethics is concerned, most critics of traditional natural law theory are bound to be most exercised by its seemingly inevitable appeal to God, and to demand a justification for it, defenders of the theory ought to get right to it. Which brings us to:

2. Divine purposes: An appeal to divine purposes would start with a traditional philosophical case for the existence of God as the Author of nature, and then argue that the purposes and ends He had in mind in creating the world can be read off from nature itself. This is best done in conjunction with a separate philosophical case for realism about forms, to give metaphysical guidance in the search for ends in nature (albeit that forms are ultimately to be understood, à la St. Augustine, as ideas in the mind of God).

One natural way – by no means the only one – that this might proceed is via an updating of the argument just alluded to, Aquinas’s Fifth Way. And it should be understood that this argument is not properly interpreted as a William Paley or William Dembski style design argument: Aquinas is not making a claim about the origin of complexity, but a claim about intentionality or “directedness.” For this reason, his argument is not a probabilistic “god of the gaps” argument that stands or falls with the adequacy of current attempts by evolutionary biologists to explain this or that biological phenomenon. It is a straightforward attempt at a demonstration, and one that still has a foundation as long as there is any genuine intentionality in the material world, even if intentionality doesn’t really exist in things like the sun and planets after all. But then, as I noted earlier, the intentionality manifested by the human mind is precisely that aspect of the natural world that materialism and mechanism have had the greatest difficulty accounting for. It therefore constitutes a fitting starting point for an argument to the existence of a Divine Mind as the only possible explanation for the existence of any finite minds.

This is not the place to develop such an argument, though John Haldane has presented something like it in Atheism and Theism, and it is something I intend to explore in detail in some work in progress. And it would, as I have said, be but one of many considerations the defender of traditional natural law theory could bring to bear in defense of the metaphysical underpinnings of his theory. The cosmological argument would be another, and that is an argument that has many able defenders in recent philosophy (including some contributors to this blog). Suffice it to say that if philosophical theism is every bit as defensible today as it ever was – and it is – then the brand of traditional natural law theory that rests on it has as strong an intellectual foundation as it ever did. Those who are interested in some references to writings by contemporary defenders of the traditional theistic arguments, and in a defense of the claim that it is perfectly appropriate to bring moral and political views that rest on theistic foundations to bear in debates about public policy, are again directed to the recent article of mine alluded to earlier.

There is another way defenders of something like traditional natural law theory might think to defend the idea of purposes in nature, though, which does not appeal either directly or indirectly to the existence of God. And that brings us finally to:

3. Naturalized or quasi-purposes: Appeals to immanent or divine purposes explicitly reject the idea that everything that exists in the natural world is governed exclusively by mechanistic principles. But the third approach I want to say something about tries to defend the idea that purposes can in some sense be said to exist in nature even if we interpret nature, and the place of human beings within it, in a purely mechanistic way.

Here I have in mind the attempted reconstruction in Darwinian terms of the notion of biological function put forward by several contemporary philosophers of biology. The idea is, roughly, that the natural function of an organ is determined by the reason for which it was favored by natural selection. So, for example, the reason teeth were favored is that since they allowed creatures having them to chew their food, they better enabled those creatures to digest that food and thereby to survive in greater numbers than creatures that lacked teeth. So, the function of teeth is to chew food. This sort of analysis is often called “naturalistic” because it appeals only to concepts already familiar in modern natural science, and does not rest on any Aristotelian or theological premises. (Obviously “naturalistic” as used in this context does not correspond to the sense of “natural” operative in traditional natural law theory.)

Michael Levin has appealed to this sort of analysis of biological function in defense of something like a traditional natural law approach to questions of sexual morality (though he doesn’t call his own approach a “natural law” view and I assume there are many elements of that sort of view, including many specific moral conclusions that it tends to be associated with, that he would not endorse). Given the analysis in question, he says, we have a perfectly naturalistic conception of function that does not even indirectly appeal to divine purposes. And so there is, even if one rejects both Aristotelian teleology and theism, a clear sense in which certain behaviors can be said to be unnatural.

The way Levin ties this into morality is to suggest that since evolution favored certain organs and capacities for certain specific purposes related to survival, it would also tend to favor the selection of certain built-in rewards for using such organs and capacities in a way consistent with their functions, and certain built-in penalties for using them in a way contrary to their functions. One of his examples involves exercise. Muscles evolved in order to enable us to escape predators, catch prey, and so forth. And obviously, a creature that regularly uses his muscles and is therefore more physically fit is going to have an advantage over one who is lazy. Evolution, Levin argues, would therefore tend to favor a genetic predisposition to find the use of muscles enjoyable, for creatures who had such a predisposition would be more likely to use them in a way consistent with their function and therefore in a way more conducive to survival. And such predispositions would still exist in such creatures even when conditions change and the circumstances that originally favored their selection no longer existed.

Such a predisposition would not necessarily be overwhelming: all things being equal, a creature will tend to find the use of his muscles enjoyable, but under circumstances where conflicting desires are easy to fulfill, he might nevertheless incline toward laziness. Indeed, in modern circumstances, where predators are rather easy to avoid and food is extremely easy to come by, this is quite likely to happen. But in that case such a creature is bound to suffer a certain penalty for his laziness, namely the loss of the enjoyment and general psychological well-being that would have resulted from exercise. He will not necessarily realize this – he may truly believe that he is happier being a couch potato than he would have been had he exercised more – but he is mistaken. Exercise will still be beneficial to us, and still promote general psychological well-being, even if we no longer need to use our muscles to catch prey and avoid predators. And in general, the use of organs and capacities in a manner consistent with their natural function will tend on balance to promote greater happiness, while their use in a contrary manner will tend to result in greater unhappiness (at least by comparison with circumstances in which people generally do use them in accordance with their natural function), whether or not people always realize this. But in that case, we have moral grounds for favoring and promoting the use of our bodily organs and capacities in accordance with their natural functions and for discouraging contrary uses.

Levin’s argument is actually much more complicated than that, but this brief sketch will convey the general idea of how evolution might be appealed to in defense of something like natural law reasoning. Another such appeal is represented by F.A Hayek’s defense of traditional moral and social rules in terms of a theory of cultural evolution. Hayek’s view is that whatever the actual reasons for which the members of a society might adopt such rules, those rules that are in fact beneficial, and in particular those that give a society adhering to them an advantage over other societies, will tend to persist while maladaptive rules will tend to die out. For societies which adhere to maladaptive rules will themselves tend to weaken and die out, taking the rules with them, while those that follow more adaptive rules will tend to thrive and displace their competitors. (Here too I am oversimplifying for brevity’s sake. A more detailed examination of Hayek’s theory can be found here.)

Hayek applies this model primarily to a defense of the moral prerequisites of the free market (private property, contract, and the like), and while he also suggests that it supports the traditional family, he does so only in a rather sketchy fashion. We might note, however, apropos of my previous post, that it is not only natural law theorists who have predicted that Western secularism might in the long run be doomed to extinction given that Western secularists tend to reproduce in far fewer numbers than either observant Jewish and Christian Westerners on the one hand, or religiously observant non-Westerners (especially Muslims) on the other. The next several decades should provide some empirical evidence of whether the “contraceptive mentality” (as Pope John Paul II called it) can pass the test of Hayekian cultural evolution.

Hayek’s view would, unlike Levin’s, count only indirectly as a naturalistic reconstruction of traditional natural law theory (and, like Levin, Hayek does not describe his position as a natural law view). For Hayek does not say anything about the functions of organs and biological capacities, but speaks rather of the functions served by various rules of conduct. Still, he does take such functions to have a normative force, insofar as he thinks that acting in a way that tends to undermine the ability of those rules to perform their functions is for that reason morally suspect. If the function served by rules safeguarding private property is to allow for stable market transactions and the prosperity that flows from them, then if we care about such prosperity we ought to promote respect for private property and discourage policies which might weaken private property, even if such policies might seem to have certain benefits in the short term. Similarly, if the function of the various traditional scruples surrounding sex is to safeguard the stability of marriage, then if we are concerned with the stability of marriage we ought to promote respect for such scruples and discourage flouting them, even if flouting them might seem to have some short-term benefits. (Here, again, I am only summarizing. For a more detailed account see again the article linked to above.)

Now, would naturalistic appeals to function of the sort advocated by Levin or Hayek provide adequate non-Aristotelian and non-theological support for traditional natural law reasoning? I think the answer must be “Yes and no.”

The difficulty is this. As John Searle has pointed out in criticizing various “biosemantic” theories of intentionality, there really is no literal sense to be made of talk of “natural functions” from a Darwinian point of view. Strictly speaking, teeth do not have the “function” of chewing food; or at least, to talk about the “function” of teeth adds nothing to saying that creatures with teeth tended to pass on their genes with greater frequency than those without. Having teeth caused greater reproductive success, and that’s it. The notion of “function,” along with related notions like “purpose,” “natural end,” and “design,” drop out as otiose. Indeed, that’s the whole point of Darwinism: to allow for a way of explaining biological complexity without having to appeal to teleological notions at all. Various organs and capacities may well operate as if they have natural functions, and it will undoubtedly be useful in determining how they evolved to think of them as if they do; but they don’t literally have functions at all.

It seems to me that Searle is right about this. If one endorses a thoroughgoing mechanistic view of the natural world, there is no room for teleology of any sort, and thus no room for any literal talk about functions. So to appeal to the kinds of “functions” Levin speaks of is really to appeal merely to ersatz functions or quasi-functions.

That doesn’t mean there can be no value in an analysis like Levin’s or Hayek’s. For it might still be true to say that to use certain organs or capacities in certain ways, or to violate certain traditional rules, is bound to have negative consequences. Precisely for the reasons Searle mentions, what Levin and Hayek have to say is fairly easily translatable into terms that make no reference to the idea of function.

But because what Levin and Hayek appeal to are not really natural ends, purposes, or functions per se, they will not have the rigid and clear-cut character that the sorts of ends and purposes appealed to in traditional natural law theory have. They will not involve participation in timeless forms, understood in either a Platonic or an Aristotelian sense, but will merely reflect certain contingent, uneven, and (given genetic engineering) possibly alterable biological patterns. And if they do not reflect anything deep and permanent in human nature, our confidence that acting contrary to them is inconsistent with human flourishing must necessarily be less than absolute. Moreover, given that the conception of rationality that tends to prevail on a thoroughgoing mechanistic view of human beings is a Humean means-ends conception, it is harder to see how the results reached via the sort of theory I’m describing could be as conclusive as those reached via traditional natural law reasoning.

In short, the traditional natural law theorist can appeal to a robust metaphysical conception of the human good which entails that certain actions are flatly incompatible with that good and thus flatly irrational, where these conclusions apply to every human being without exception. But a “naturalistic” reconstruction of natural law reasoning can appeal only to rough and contingent generalities about human nature that support, at most, conclusions to the effect that certain behaviors will, on balance and all things being equal, tend to lead to certain bad consequences for most individuals and/or for society at large – and where if one happens not to care about those consequences, there is no reason for him to be moved by the reasoning in question.

So, certain conclusions reached by traditional natural law reasoning can still be defended even when one rejects its metaphysical presuppositions, but not with the same decisiveness. Traditional natural law theory is best defended, then, within the context of philosophical theism. And if that means that it must wear its metaphysical presuppositions on its sleeve, fine. It will at least in this way be more honest than most secular theories, which have metaphysical presuppositions just as controversial, though rarely acknowledged as such. It is about time philosophers abandoned the fatuous pretense that ethics can be done without metaphysics.