On Descartes, Dennett, and Design (Cicero's Posidonian Argument, Reconsidered)

Imo indocti haec magna cum voluptate spectabunt et facillimo negotio ea quae nunc nullo modo capiunt, intelligunt.--I. Beeckman (1629), commenting on the effect of a planetarium.

Last week I had the good fortune to participate in Daniel C. Dennett's lectures, “Evolving Minds: From Bacteria to Bach and Back,” which he gave at the invitation of the Ferrater Mora Chair in the lovely town of Girona (see here for more info). During one of our breaks, we happened to discuss Dennett's "Descartes's Argument from Design" (Journal of Philosophy, 2008), in which he draws on Descartes's response to Caterus to make sense of Descartes's a posteriori argument for the existence of God (in Meditations 3). The key passage, which -- as Dennett notes (338) -- is repeated in Principles of Philosophy is, "if someone possesses the idea of a machine, and contained in the idea is every imaginable intricacy of design, then the correct inference is plainly that this idea originally came from some cause in which every imaginable intricacy really did exist, even though the intricacy now has only objective existence in the idea."

The argument from intricate machine to designer and then from most intricate design to perfect/godly designer would have been familiar to Descartes from various sources. But the most beautiful version of the argument is in Cicero's On the Nature of the Gods (recall), where a working planetarium (ascribed both to Posidonius and to Archimedes) is used to make the point. That Cicero may well be part of Descartes's inspiration is suggested by the significance of Archimedes's (planetary) sphere in both Cicero's On the Nature of the Gods (and some of his other relevant works, especially Tusculan Disputations [which is an important text in Descartes's development; see Menn]) and Descartes's Meditations (admittedly, Descartes is more interested in Archimedes as a mathematician than planetarium builder). [Above I link to Beeckman's treatment which is undoubtedly inspired by Cicero.]

Dennett, who has many astute comments on Descartes's argument, does not comment on the fact that at first blush, it would seem that Descartes innovates on the traditional argument by insisting that an idea or (judging by his description) an intricate blue-print can do the relevant work in the argument. It's one thing to take a working (or empirically succesful) planetarium "to Scythia or to Britain" where "no one in those barbarous regions would doubt that that planetarium had been constructed by a rational process," it's quite another point to a blueprint of an intricate machine and, say, see.

But the true novelty of Dennett's reading is that he ultimately interprets Descartes as claiming that Descartes, too, appeals to a working machine in the argument to design:

[Descartes] had used that very idea [of God] and no other as the sole foundation for his theory of... Le Monde...The fact remains that it was a huge theory, full of intricacy, remarkably self consistent, often fiendishly persuasive even in today's hindsight. Any idea that could generate such a stunning intellectual edifice would be a prodigiously fecund idea...because his idea is not just made of lots of good parts (ideas available to everybody), and not because his idea is of a wonderful thing? God; it is because his idea is (he thought) a stunningly well-designed engine of scientific discovery.

That is to say, on Dennett's reading, Descartes thinks he can point to his whole scientific theory as the working machine that represents and predicts the machinery of the universe. This is not the place to what degree pointing to Le Monde or the Principles of Natural Philosophy will really be more persuasive (in such a design argument context) than pointing to a working planetarium. Rather, my point here is that on Dennett's interpretation of Descartes, his scientific theory of the universe presupposes Godly design. Now the nature of this presupposition is, of course, a tricky matter -- and it took more than a century to work this out, including hard work by Toland, Clarke, Hume, Adam Smith, and Kant --, but we can represent the logical form of Descartes's argument, as interpreted by Dennett, as follows:

(I)                A condition of the possibility of (an intended) successful scientific representation of nature is that nature is not the product of chance, but (I*) design. &

(II)               Science is successful.[1]

(III)             ∴ There is a designer (or nature is designed).

I call this the transcendental version of the Posidonian argument. This argument became hotly debated in the eighteenth reception of Spinoza's and Newton's philosophies (often with a nod to Cicero and Posidonius/Archimedes) and I have been working on a short book on this topic. But if Dennett is right then the transcendental version of the Posidonian argument is not a by-product of the scientific revolution, but it's right there at the heart of that process that was once called the mechanization of nature. 

 

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[1] For simplicity’s sake, I have suppressed the temporal dimension. But one can also formulate (ii) as ‘Science has a history of success.’ 

 

 

Comments

[Brad]

There's an alternative form of the argument that brackets the question of the success of the representation, and appeals instead to its perfection (or wonderfulness, as Dennett puts it). Dennett says some things that suggest your reading, but I wonder if the alternative reading might not be what he has in mind? It would certainly make the innovation you attribute to Descartes, of appealing to an idea rather than a thing, more striking.

[Eric Schliesser]

Brad,
I think the two versions of the argument are to be found both in Cicero and both in Descartes. The perfection argument is the official one of Meditations 3 (and is already familiar prior to Dennett's paper--of course Dennett's paper explains why it would have been somewhat plausible to Descartes and this turns out to be quite fascinating in its own right). Indeed, I think the appeal to perfection is a recurring theme throughout the tradition of arguments to design.
Having said that, what I call the transcendental version of the Posidonian argument is much less familiar and I think one reason for this is that it undercuts the now common idea of science as a kind of neutral mechanism/instrument in establishing the existence of any entity (in this case god).

[Alan Nelson]

Dennett's allusion to Descartes seems stretched. Any large, but merely potentially infinite amount of objective intricacy (or being) can be attributed to a sufficiently developed finite intellect. The argument for God's existence requires an actual, completed infinity of objective reality.
Descartes uses intricacy as an example to motivate the question of the source of the objective being/intricacy.

[Eric Schliesser]

Alan, Dennett's argument in the Jphil is, while speculative, quite elaborate. So don't be mislead by my terse presentation.