Haldane on Nagel and the Fifth Way

Next week I’ll be at the Thomistic Seminar organized by John Haldane.  Haldane’s article “Realism, Mind, and Evolution” appeared last year in the journal Philosophical Investigations.  Thomas Nagel’s book Mind and Cosmos is among the topics dealt with in the article.  As Haldane notes, Nagel entertains the possibility of a “non-materialist naturalist” position which:

would explain the emergence of sentient and then of rational beings on the basis of developmental processes directed towards their production.  That is to say, it postulates principles of self-organization in matter which lead from the physico-chemical level to the emergence of living things, which then are further directed by some immanent laws towards the development of consciousness, and thereafter to reason for the sake of coming to recognize value and act in response to it, a state of affairs which is itself a value, the good of rational life. (p. 107)

As the phrases “directed towards” and “immanent laws” indicate, what Nagel is speculating about is a return to a broadly Aristotelian notion of natural teleology.

 
Three views on natural teleology

As longtime readers of this blog know, an Aristotelian notion of natural teleology contrasts with the sort found in writers like William Paley, and can be illustrated via simple examples.  The teleology or “directedness” of a watch towards the end of telling time is extrinsic to the parts of the watch, insofar as there is nothing in the bits of metal and glass that make up the watch by virtue which they inherently serve that end.  The time-telling function has to be imposed on them from outside.  An acorn, by contrast, is inherently directed towards the end of becoming an oak.  That’s just what it is to be an acorn.  Whereas the teleology of the watch is extrinsic, the teleology of the acorn is intrinsic.  For Aristotle, that is what makes an acorn a natural object whereas a watch is not natural in the relevant sense but artificial.  Paley’s view that natural objects are to be thought of on the model of watches and other human artifacts would in Aristotle’s view simply be muddleheaded.  Precisely because they are natural -- and thus have immanent rather than extrinsic teleology -- acorns and the like are not like watches.

What explains the teleology of a natural object?  The extrinsic teleology of a watch derives entirely from the maker of the watch, so that if natural objects are as Paley says they are, their teleology must derive entirely from some “designer.”  For Aristotle, though (as usually interpreted), since the teleology of a natural object follows from its nature, there is no need to look beyond its nature to explain it.  That is not because Aristotle denies the existence of God -- on the contrary, he famously argues for the existence of a divine Prime Mover.  He just doesn’t think that a thing’s having teleological features is among the things that require a divine cause.

Aquinas takes a third position.  In his view, the proximate source of a natural object’s teleological features is just its nature, and in that sense natural teleology is, as Aristotle holds, immanent.  But the source of a thing’s nature, and thus the ultimate source of its teleological features, is God, so that in that sense teleology is, as Paley holds, extrinsic. 

Aquinas’s position on teleology (or final causality) in this respect exactly parallels his position on efficient causality.  On the latter subject, Aquinas maintains, on the one hand, that though created things or “secondary causes” derive their causal power entirely from the divine first cause, these created or secondary causes really are true causes.  It really is the sun that melts the ice cube in your drink, it really is the poison oak that gives you a rash, it really is the ointment that speeds up the healing of that rash, and so forth.  That is to say, the “occasionalist” view that it is only ever really God who causes anything, with secondary causes being illusory, is one that Aquinas rejects.  On the other hand, Aquinas also rejects the view that secondary causes can ever operate even for an instant without God imparting their causal power to them.  The notion that secondary causes could so act tends toward deism, which Aquinas would regard as an opposite error from that of occasionalism.  Aquinas’s view, known as “concurrentism,” stakes out a middle ground position.  (See Fred Freddoso’s important papers on this subject, here, here, and here.)

Aquinas’s views on final causality and efficient causality are closely connected.  For Aquinas, the only way to make sense of how it is that an efficient cause A reliably generates a specific effect or range of effects B is if generating B is the end or final cause toward which A is inherently directed.  (This is the Scholastic “principle of finality.”)  Inherent or intrinsic directedness toward an end thus goes hand in hand with having efficient casual power.  If we take the Paleyan view that things have no immanent teleology but only extrinsic teleology, then we are (given Aquinas’s metaphysics of causation) implicitly denying that they have genuine efficient causal power.  That would leave the false appearance of their having it a result of God’s making things happen in such a way that objects seem to have causal power (which is the occasionalist position).

So, to avoid occasionalism, we need to affirm that a natural object’s efficient causal power and its finality or teleology both have a proximate ground in the nature of the object itself, as well as an ultimate ground in the First Cause.  This is also what makes natural science possible.  Just as both the theist and the atheist can know the efficient causal powers of oxygen, hydrogen, sunlight, ointments, etc. just by studying these things themselves, so too can both the theist and the atheist know the teleological features of things just by studying the things themselves.  Both efficient causal power and finality are there to be seen in things, whether or not someone is aware that they could not be there in the first place, even for an instant, unless both features were continuously imparted by the divine First Cause.  (Compare: You can see a thing’s reflection in the mirror whether or not you realize that it can only be there even for an instant if there is something beyond the mirror which is being reflected.) 

(I discuss final causality and its relation to efficient causality in depth in Scholastic Metaphysics, especially in chapter 2.  I discuss and defend Aquinas’s reasons for affirming both a proximate ground of a thing’s finality in its own nature and an ultimate ground in God in my Nova et Vetera article “Between Aristotle and William Paley: Aquinas’s Fifth Way.”) 

Nagel and the Fifth Way

That brings us back to Haldane and Nagel.  Nagel, again, at least toys with the idea of returning to an Aristotelian notion of teleology or finality as immanent to the natural order.  Because he sees teleology as grounded in nature itself rather than entirely extrinsic, his view is not like Paley’s.  Because he sees this grounding in nature as ultimate rather than proximate, his view is not like Aquinas’s either.  In this way Nagel hopes to be able to move away from materialism, with its anti-realism about teleology, to a robustly teleological position, but without affirming any brand of theism.  Nagel writes:

The teleology I want to consider would be an explanation not only of the appearance of physical organisms but of the development of consciousness and ultimately of reason in those organisms…

Teleological laws… would be laws of the self-organization of matter, essentially -- or of whatever is more basic than matter…

A naturalistic teleology would mean that organizational and developmental principles of this kind are an irreducible part of the natural order, and not the result of intentional or purposive influence by anyone.  I am not confident that this Aristotelian idea of teleology without intention makes sense, but I do not at the moment see why it doesn’t.  (Mind and Cosmos, p. 93)

Now, Aquinas’s Fifth Way is intended to show that this sort of position cannot be maintained.  Even immanent teleology necessarily leads to theism, in his view, even if via a route less direct than the one Paley and his followers take.  (Again, I’ve expounded and defended his argument at length elsewhere -- in greatest depth in the Nova et Vetera article, and also in my book Aquinas.)

Of the Fifth Way, Haldane notes:

First, unlike the famous design argument of William Paley and the contemporary “irreducible complexity arguments” of Michael Behe and others, it does not rest on claims about the structural relationship of parts within organs but is perfectly general.  Second, it is teleological across the range of non-rational nature, hence overlaps significantly with the positive part of Nagel’s preferred solution. (p. 111)

Haldane then briefly sketches a way in which Nagel’s position might be taken in a Fifth Way-style direction.  He appeals to the

Thomistic principle… that an activity or a series of activities related to one another as parts of a process can never exceed the power of the cause that operates to produce and sustain them.  Another way of putting this is to say that the highest actuality or reality that might be obtained is but an expression of what was already present from the beginning.  Unified processes on this account unfold [and] they do not introduce what was hitherto wholly non-existent. (p. 110)

This is a variation on what is sometimes called the Scholastic “principle of proportionate causality,” to the effect that whatever is in an effect must be in its total cause either formally, virtually, or eminently.  (I expound and defend this principle too in Scholastic Metaphysics, at pp. 154-59.)

Haldane suggests that Nagel might agree with this principle as Haldane states it, insofar as Nagel proposes that rationality, consciousness, and the like might have developed via principles that have always been immanent in the natural world from the beginning, long before the rise of rational and conscious organisms.  But Haldane suggests that consistent application of the principle may lead Nagel in just the sort of theistic direction he wants to avoid going in:

[A]pplication of the principle that the highest actuality must be present in the cause(s) out of which it emerges implies for Nagel’s claim that the developmental process has led to rational beings that the causes must contain reason and, insofar as it is directional, knowledge also.  But a cause that is endowed with knowledge and intelligence by whom all natural things are directed to their end comes close, perilously close for Nagel to the conclusion that the cosmos is an effect of a transcendent purposive agent. (p. 111)

I think this is a very interesting suggestion, though it might be argued that Haldane moves too quickly to a “transcendent” cause.  For someone might claim that even if reason and knowledge must in some sense be present all along, they might still be present in a way that is wholly within the natural order.  In other words, one might take Haldane’s proposed emendation of Nagel to lead at best to an essentially Stoic natural theology, which affirms a divine logos immanent to nature.  This would be a variation on pantheism rather than theism.

To get to theism, we need to add a premise to the effect that the world itself cannot be the terminus of explanation.  That’s not hard to show given other elements of Thomistic metaphysics.  The world is, for example, a mixture of actuality and potentiality, and thus requires an actualizing cause.  Only what is pure actuality can be an ultimate cause -- can be what causes everything else without even in principle requiring, or indeed even being capable of having, a cause of its own. 

It seems to me, though, that this would give us a variation on a cosmological argument rather than a Fifth Way-style argument.  The idea would be that an argument like Aquinas’s First Way or Second Way gets us to a transcendent First Cause, and that Nagel’s position as emended by Haldane would entail that this First Cause must contain something like reason and knowledge; for reason and knowledge are in the effect, and whatever is in the effect must in some way be in the cause.

I’ve argued that a First Cause has to have intellect on somewhat different grounds (e.g. in the second half of my lecture “An Aristotelian Proof of the Existence of God”).  And the Fifth Way, as I have expounded and defended it, is considerably different from the argument Haldane sketches.  But it seems to me that his proposal is interesting and worthy of further development.