A post on Newton's and Spinoza's metaphysics, Pt 1. Nature does nothing in Vain.

I am not sure I have ever seen it remarked — but I am happy to be corrected — that the implied pay-off of Newton’s first ‘rule of reasoning’ that (in the Cohen and Whitman translation) “Nature does nothing in vain” is a specific target of the famous appendix to the first part of Spinoza’s Ethics. Here’s how Spinoza puts it (in Curley’s translation): “while they sought to show that Nature does nothing in vain (i.e., nothing not of use to men) they seem to have shown only that Nature and the gods are as mad as men.”

Now, Spinoza’s Ethics was published in 1677. And the first version of the Principia in 1686. In the first edition, the passage I just quoted was a ‘hypothesis.’ It became an even firmer ‘rule of reasoning’ in the second 1713 edition. This matters because while it is by no means obvious that Spinoza and Spinozism (and its refutation) are at all significant in the drafting of the first edition of the Principia, I have spent a good part of my adult life trying to show that some of the more significant non-technical additions (not the least the General Scholium) and re-castings are best viewed in this light. (I have collected my cumulative argument in Newton’s Metaphysics: Essays, which would make a nice albeit somewhat expensive holiday present—although I note that the cover art alone is worth the price.)

Now, it never occurred to me to treat Newton’s embrace of the first rule of reasoning as an implied critique of Spinoza because they seem to be talking about two different kinds of explanatory strategies when they reject and accept nature does nothing in vain. For, when in rule 1, Newton embraces it he is explicitly denying that nature indulges in ‘superfluous causes.’ That is, he is ascribing a kind of principle of economy to nature (or a regulative principle of nature) such that in our explanations ‘no more causes of natural things should be admitted than are both true and sufficient to explain their phenomena.’ How we should think about the implied relationship between nature and our explanations of it is worth further reflection, but let’s leave that aside. The underlying idea is straightforward enough, when we can avoid baroque causal theories/models, we should opt for simpler ones.

In context of the Appendix of Ethics 1, Spinoza’s critique of the application of nature does nothing in vain is really a critique of the use of final causes, and especially the tendency to treat the natural world as ordered by benevolent god(s) serving our needs: “from the means they were accustomed to prepare for themselves, they had to infer that there was a ruler, or a number of rulers, of Nature, endowed with human freedom, who had taken care of all things for them, and made all things for their use.” Lurking here is a wider critique of special providence.

This last point can be illustrated. In fact, in his discussion, Spinoza clearly implies that the ‘madness’ that follows from the embrace of ‘nature does nothing in vain’ is a kind of specious multiplication of causes. For, the superstitious mind searches for particular causes to explain individual fortune and misfortune. And so implicates god(s) as a first and/or direct cause of all particular events that cry out for an explanation. Each setback is God’s punishment, one’s thriving God’s reward, and so on. So, despite superficial disagreement one may well think that Newton and Spinoza are actually agreeing here—both being on team Enlightenment.

But things are not so simple. First, sophisticated readers know that Newton is not a critic of final causes, so we can’t automatically assume that a view like his is definitely not the (anticipated) target of Spinoza’s philosophy. Second, what I call ‘Newton’s principle of economy’ may well presuppose an ordered-ness that bottoms out in some kind of final cause.

In a famous (2001) article, James Lennox alerted us that ‘nature does nothing in vain’ was deployed in the cutting edge of early modern science. He starts his article with two quotes from Harvey, and he argues that in Harvey they are not mere ornaments, but rather that the principle plays a role in the context of discovery as a regulative constraint on hypothesis formation. (p. 219-220)

Now, Lennox shows that in Aristotle (and in particular Aristotle life sciences) the ‘Nature does nothing in vain’ principle is used as a premise in an argument to explain the absence of a feature, which were it present, would be superfluous. (p. 214) And the reason why this explanation is required is that what counts as an explanation is, in part, relative to the interests and needs/flourishing of the animal or species being described. So, the principle is itself a feature of functional explanations, that is, in terms of final causes. (If this is too terse do read Lennox!)

One may well wonder what element in nature or a species is not doing something in vain. And if I understand Lennox’s interpretation of Aristotle correctly, the “formal nature of the animal” is “the causal agent dynamically producing and maintaining the composite substance.” (p. 201) Keep that in mind.

Of course, Lennox’s interpretation of Aristotle has been contested (or at least refined). Gottlieb and Sober (2017), for example, suggest that the nothing in vain principle has an empirical justification in Aristotle and, more important, that it presupposes what they call “Aristotle’s natural state model, according to which an organism will develop toward its natural state unless interfering forces prevent that from happening.” (They plausibly call this model ‘Newtonian,’ although I would have used ‘Cartesian.’) And, in fact, they think in Aristotle this has a teleological component such that “Organism O has trait or structure X by nature if and only if O will develop X if its development is unimpeded and X is the best trait (among the alternatives) for O to have, given the kind of organism that O is.”

Now, interestingly enough, Newton’s second rule is said to follow from (“therefore”) of the principle of economy: “the causes assigned to natural effects of the same kind must be, so far as possible, the same.” And the very first example Newton gives is not from astronomy or optics (these do follow), but from the life sciences: “the cause of respiration in man and beast.” So, Newton invites his reader to treat his principle of economy as at least also being about the same kind of topics as Aristotle’s and Harvey’s science(s). In fact, it’s not a stretch to see Harvey’s experiments on the circulation of blood in many different kinds of animals as the prototype for the kind of explanatory parsimony Newton is advocating in the second rule.

I don’t mean to suggest Newton’s account of the principle is identical to Harvey’s. Newton’s regulative principle of nature — his principle of economy — has, thus, two epistemic or heuristic payoffs: an injunction against superfluous causes where one can do with less, and an injunction to treat, where possible, very similar phenomenon in one species as belonging to the same kind despite appearing in another species. This is not the same use as we find in Aristotle or Harvey. And the reason for that is, I think, that Newton aims the ascription of causes to involve something quite general in a way that Aristotle and Harvey don’t quite foresee; the paradigmatic causes in Newton are forces, which are themselves abstract quantities (see Smeenk & Schliesser), not particular/localized etiologies or functions.

I want to pause for now. But I want to alert you to my next step. In a justly admired paper, Karolina Hubner (2015), has argued quite persuasively that the paradigmatic case of causation in Spinoza is a formal-causal relation, that is, is fundamentally a relation of inference of a property from a thingʼs essence. And while there is a route into this way of thinking via geometry, it also has (via Descartes) an Aristotelian provenance in the very material we have been discussing.

Stay tuned.