Monday, October 23, 2017

Existence, causation and individuation

Suppose a cause C produces horses, in the following way:

  • When C produces a horse, a horse instantly comes into existence made out of some mass of non-equine matter M.

  • The genetic makeup of the resulting horse is randomly distributed over all DNA compatible with being a horse.

(Imagine lightning striking a bog and randomly turning the bog mass into a horse.)

So now suppose that in world w1, a female Arabian, Green Lightning, comes into existence as a result of C, while in w2, a male Exmoor pony, Tigger, comes into existence as a result of C.

Presumably, Green Lightning and Tigger are numerically distinct horses. Why are they distinct? Presumably because they are qualitatively different—specifically, because their DNA is different. If in w1 and w2, C respectively produced horses that were exactly alike out of M, those horses would have to have been numerically identical. (Haecceitists will disagree.)

But now we have a puzzle for Aristotelians. Both Green Lightning and Tigger are of the same species. (If you think that breeds or sexes make for different metaphysical species, modify the example and make them be of the same sex and breed, but still very different from each other.) Let the Fs be the qualitative features that Green Lightning and Tigger initially differ in.

  1. The Fs in are accidents in the Aristotelian sense: they are accidental to their horsehood, which is their form.

(They may not be accidents in the contemporary modal sense. It may be that it is impossible for a horse to be of another sex than it is.)


  1. The Fs make Green Lightning be distinct from Tigger.

  2. If what makes Green Lightning be distinct from Tigger are the Fs, then the Fs help make Green Lightning be Green Lightning.

  3. Nothing that helps make x be x can be explanatorily posterior to x.

  4. So, the Fs are not explanatorily posterior to Green Lightning. (2-4)

  5. The accidents of x are explanatorily posterior to x.

  6. So, the Fs are explanatorily posterior to Green Lightning. (1,6)

  7. Contradiction! (5,7)

The case where C makes a horse come into existence from non-equine matter makes the above argument a bit more vivid. In the ordinary case of equine reproduction, a sperm and egg contribute their DNA and give rise to the DNA of the offspring. There it could be argued that the relevant thing that helps make the resulting horse be the horse it is is the DNA in the sperm and the DNA in the egg.

One could conclude that a horse can’t come into existence from matter that doesn’t already contain implicit in it the DNA of the horse. But that is implausible, especially since God could create a horse even without any matter.

This puzzle worries me a lot. I initially thought it was a special puzzle for four-dimensionalist temporal-parts Aristotelianism, because it showed that the first temporal part of the horse was explanatorily prior to the whole, whereas Aristotelianism forbids parts to be prior to wholes. But then I realizes that the same point could be made about accidents without reference to four-dimensionalism.

Here is my best solution. There is something about Green Lightning that is prior to her being Green Lightning. It is her being caused by C to exist with the Fs (i.e., her being caused by C to exist as a female Arabian, etc.). Admittedly, that sounds just as much as an accident of Green Lightning as the Fs are. It’s not Green Lightning’s form, so what else could it be but an accident? There is no answer in Aristotle, but there is a potential answer in Aquinas: this could be Green Lightning’s act of being, her esse. And it is not crazy to take Green Lightning’s esse to be something that (a) is prior to Green Lightning, (b) Green Lightning could not exist without, and (c) an individuator of Green Lightning.

This reminds me of a line of thought in the Principle of Sufficient Reason book where I argued that the esse of a contingent being is its being caused. If my present solution is correct, that was only a partial description of the esse of a contingent being. And I think there may well be an argument for the principle that ex nihilo nihil fit in the vicinity, just as in the PSR book—for it is absurd to think that anything contingent could be prior to x if x has no cause, while this esse is something contingent.


Christopher Michael said...

There is an equivocation on "explanatorily posterior" between 5 and 7. What explanation do you want to give? If it's the explanation of what grounds what, then accidents are explanatorily posterior to their substances. But if it's the explanation of what individuates what, then accidents are explanatorily simultaneous with their substances. All individantia are simultaneous with their individuanda in explanations of individuation.

Alexander R Pruss said...

There is no equivocation. Sure there is more than one kind of explanation, but they doesn't make for equivocation, just as the fact that there is more than one kind of animal doesn't make "animal" equivocal.

Note that one can also rephrase in terms of grounding. The substance partially grounds the Fs, but the Fs seem to partially ground the substance.

Christopher Michael said...

Oh, well, if you read the argument with a simpliciter sense of explanatory posteriority, then 4 is false. For example, Green Lightning's soul helps Green Lightning be Green Lightning, but Green Lightning's soul depends on him and so is explanatorily posterior to him in at least this sense and therefore also in the simpliciter sense.

In your grounding version of the argument, it is false that accidents partially ground the substance. They individuate it. Individuation is not grounding, at least in part because individuation presupposes existence and existence presupposes ground. The question of what distinguishes A from B simply doesn't arise until we know that A exists and B exists.

Alexander R Pruss said...


Very interesting about the soul. I think this could be a good reason to think the soul is explanatorily prior to Green Lightning: esse, then soul, then accidents. Or perhaps the contribution that the soul is thought to make to Green Lightning's identity is already made by the esse, because it is the esse of a horse, which naturally gives rise to a horse's soul and all the rest of the horse. (Perhaps the esse of Green Lightning is more fully: to be caused to be a horse with Fs.) I don't know. But I think circular explanation and grounding are absurd no matter. I know some people think it's OK when the explanations or groundings are of different kinds, but I think that's cheating: if A depends on B, B can't depend on A, no matter how one distinguishes "depends".

"The question of what distinguishes A from B simply doesn't arise until we know that A exists and B exists."

But in my story, only GL exists: Trigger could have existed in GL's place instead, and if the story is understood the way I intended it there is no possible world where both GL and T exist. And yet the question of distinction arises. We need to distinguish GL not just from other existent things but also from things that could have existed.

Without identity there is no entity, the Quinean adage goes, and I think the Quinean adage is quite correct at least of substances. For a substance, at least, to be is to be a particular thing. So the particularity needs to be there, and once the particular is there, the individuality is.

Miguel said...

Why do you always use horses for your examples? Why not lions, elephants, or maybe seals?

Theophilius said...

Uhm... what about distinction made by *some* mass of non-equine matter that becomes *that* mass of equine matter once GL and-or Trigger pops into existence?