Wednesday, February 17, 2016

Aristotelian perdurance

The perdurantist thinks that we are four-dimensional beings made up of three-dimensional slices, temporal parts, from which we inherit our changing properties such as thinking. One good reason to deny perdurance is that implies that our thinking is derivative from another entity's thinking, namely from the part's thinking, pace Andrew Bailey's very plausible thesis that our thinking does not derive from another entity's thinking. Another issue is that perdurance has at most a 50% chance of being true for me: since the slice thinks the same thoughts as the four-dimensional being, I have at least a 50% chance of turning out to be the slice--contrary to perdurance.

But there is an interesting Aristotelian version of perdurance. I am a four-dimensional being, but I have a sequence of special accidents Dt corresponding to the times t at which I exist. Then all my changing features are grounded in features of these accidents. For instance, I am thinking at t provided that Dt is thinking*, where thinking* is whatever feature of an accident Dt that makes the possessor of Dt be thinking. For categorial reasons, thinking* isn't thinking: only substances think, but non-divine substances think in virtue of having an accident that in turn is thinking*.

What are the Dt accidents? One option is that they are the accident of existing at t. But perhaps there is a more Thomistic option: perhaps in the case of material substances they can be identified with something like Thomas's accidents of dimensive quantity. Thomas thought that material substances had a special accident, a dimensive quantity, and all their other accidents were in turn accidents of its dimensive quantity. This is a very similar role to that played by Dt. Or, perhaps, we could take Dt to be an accident of occupying such-and-such a three-dimensional region of four-dimensional space. There is room for further research here (and if anybody wants to work more out and co-author, they are very welcome).

There is a major difference in outlook between this and typical perdurance pictures. On typical perdurance views, the slices are prior to the four-dimensional whole. On this Aristotelian perdurantism, the Dt accidents are, like all accidents, posterior to the substance, which is four-dimensional. Apart from this, the view might not be that distant from standard perdurantism. I have proposed in another post that an Aristotelian could identify parts with certain kinds of accidents. On that identification, the Dt accidents could turn out to be parts. But the difference in outlook remains: the parts really are just accidents of the whole. And the parts don't have the same features as the whole does. They have features for which we have no names, features we can only identify as that feature of the accident that grounds the substance as being F.

This post is really just a combination of this and this.


Domenic Marbaniang said...

Peter van Inwagen considered people who suppose that there are "temporal parts" or "slices" as "victims of seductive and incoherent pictures". Philosophers who treat adverbial phrases as adjectives are guilty of adverb-pasting, he said. Do you think your models steer clear of this fallacy?
Secondly, I do not see how any idea of temporal slices could still rationally solve the paradox of change. A "temporal part" is a name, an identifier, that itself should be infinitely divisible into "temporal parts". Even if treated as sets, the paradox is not resolved.

Peter said...

Thanks for the post—this is a fascinating idea. I apologize for the long comment, but there seems to be much to wonder about this view. You say there is still a lot to work out, but I was wondering if you have filled this out more than the post explicitly says. So, trying to work some of the details out, I had a number of wonders. Trying to keep this comment from getting out of hand, I will mention one:

Consider your claim that “Dt is thinking*, where thinking* is whatever feature of an accident Dt that makes the possessor of Dt be thinking.” We might speak of this in terms of grounding – that my thinking is grounded in Dt’s thinking*. It seems there are two different basic versions (well, perhaps many more, but let’s think about these two): it is true that I am thinking because it is true that Dt is thinking* (grounding as a non-truth-functional sentential connective or as relation between facts) or that one accident, my thinking, bears some grounding or ontological dependence relation to another, which is Dt’s thinking*. At first, I preferred the latter, but I am starting to wonder if we can get by without any accident of thinking at all. Instead, we would simply say that it is true that Peter is thinking, and what this means is that I possess some accident or mode, which itself possesses an accident of thinking*. I think I would be less hesitant to take this view with other accidents: I have no accident of being sunburnt; the only accident in the neighborhood is being sunburnt*, which is an accident of Dt. We truly say, however, that I am sunburnt in virtue of possessing an accident which itself has the accident of being sunburnt*.

Did you have one of these two views of grounding in mind here? Do you think it is important to think of this one way, rather than another?

Alexander R Pruss said...

I was thinking only of the first view. The second is interesting, though.

I also think it's worth exploring whether one could have a variant view on which Dt's thinking* is grounded in my thinking.

Peter said...

Thanks for your reply. Another area that seems to need filling out is understanding the dependence relations in a nested mode ontology. This seems related to defining our categories. On one standard view, substances are concrete things that cannot inhere in other things, and can have other things inhere in them, while accidents must (or perhaps can, if we wish to make room for Aquinas’s view of transubstantiation) inhere in other things, but cannot have other things inhere in them. But this won’t do here. Instead, we must say that accidents both can inhere in other things, and can have things inhere in them. If we think these categories are distinguished by their independence from other things, then perhaps we should think of three categories, rather than two. We have substances, which cannot inhere in other things, we have those modes which cannot have other things inhere in them, and then we have an amphibian category, capable of inhering in other things and having other things inhere in them.

Whether we grant this as a third category or not, it seems to bring to light a question about what inherence means. Particularly, consider thinking* which inheres in Dt which inheres in Peter. Should we really consider the relationship that thinking* bears to Dt to be the same sort of relationship that Dt bears to Peter? In both cases, I take it, it is clear that there is a relation of ontological dependence between one and the other. If we think of accidents or modes as ways of being, then we should ask whether thinking* makes Dt be a certain way. Perhaps yes, although perhaps thinking so betrays a kind of category mistake, that claiming ways can be in different ways substantializes them a bit too much. I wonder whether an intermediate view might work here, one where thinking* inheres ultimately in Peter, but does so only in virtue of bearing some non-inherence relation to Dt. But Perhaps this wouldn’t help us solve the problem of temporary intrinsics.

What did you have in mind in constructing your view? Do you think the best way to go is with a substance-mode ontology (rather than claiming things like Dt are members of a third group)? And do you think it is best to think of all the relations in question as inherence relations?

Alexander R Pruss said...

I was just thinking of two categories as relevant: substances and modes.

I do worry about your substantializing of the modes objection.

Note that these questions come up independently of the time issue. I eat quickly and run slowly. It's plausible to say is that my eating has quickness and my running has slowness

The full view I have in mind also has essences. These are first-level modes. Thus, when I run slowly, I have the mode of humanity, which has a Dt mode, which has a mode of running*, which has a mode of slowness.

Christ, as far as we know uniquely, has two essences: a mode of humanity and a mode of divinity (which is identical in substance with him: in this case the same entity is both mode and substance, which complicates things).

Peter said...

Thanks for the response; I think this is a very interesting view.

Concerning dependence relations, do you think that I have my essence in the same sort of way that a mode of running* has slowness (inherence or instantiation or whatever)?

Alexander R Pruss said...

I don't know. It's a very good question, tho'.