Wednesday, December 17, 2014

A perdurantism without temporal parts

Standard perdurantism holds that we are four-dimensional worms made up of three-dimensional temporal parts. Many of the changing properties that we think of ourselves as having directly, we actually have derivatively from the temporal parts. Thus, I am typing a post in virtue of having a temporal part typing it up, and I am conscious of the screen in front of me in virtue of a temporal part of me being conscious of it.

Standard perdurantism has many problems, for instance:

  1. Perdurantism commits one to proper parts, and implausibly thin and hyperplanar ones.
  2. Surely I am that entity which is non-derivatively consciously rather than that entity which is derivatively conscious.
  3. Perdurantism normally comes along not just with slices, but thicker temporal parts. But then Merricks argues that we cannot know how old we are. For all I know, I might be the temporal part from five minutes ago until now (in which case I am five minutes old), or from ten minutes ago until now (in which case I am ten minutes ld), and so on. Only a handful of temporal parts containing my present stage have the age I think myself to have, so probably I don't have the age I think myself to have.

There is, however, a perdurantism without any of these problems, if one accepts the right kind of trope theory. Suppose I exist at t. Then my existing at t is a trope of me, call it et. At least unless t is the first moment of my existence, et is an accidental trope: if I perished before t, then I wouldn't have had et. (If essentiality of origins holds, then it is an essential property of me that I exist at the first moment of my existence.) Note that I am not committing myself to the controversial thesis that existence is a property. Even if existence isn't a property, it is plausible that existence in a location—i.e., spatial locatedness at x—is a property. And if so, then why shouldn't temporal locatedness at t be a property?

I now suppose that I am a four-dimensional entity that has (where the "has" is not tensed) all of the et tropes (where t is a time during my existence): it is true to say that I exist at all these times. But many of the temporally qualifiable predicates, like "is conscious" and "is bent", that apply to me apply in virtue of et itself having certain tropes. Thus, I am now bent or conscious in virtue of enow having a certain bendedness or consciousness trope.

Strictly speaking, it's not enow that is bent or conscious, but it has the kind of trope which makes that substance that has the enow trope be bent or conscious. Compare this: If I am gorging myself, then that happens in virtue of an eating trope itself having a gorging trope. But the eating trope isn't gorging itself. It is I who am gorging myself. So the gorging trope is a trope of eating such that any substance that has the eating trope with the gorging trope gorges itself. The gorging trope, thus, makes me—the substance—be a gorger and makes my eating trope be not a gorger, but gorgingly. This is linguistically tricky.[note 1]

On standard perdurantism, I persist over time in virtue of having temporal parts that exist at various times. On this trope perdurantism, I persist over time in virtue of having temporal locatedness tropes.

On this theory, the temporal locatedness tropes et play the role of the temporal parts of standard perdurance. But they aren't parts. So we aren't committed to parts, much less implausibly thin and hyperplanar ones.

We also do not have the problems in (2) and (3). For while I am conscious at t in virtue of et having a certain consciousness trope ct, that consciousness trope doesn't make et be conscious. So while I am conscious in virtue of something other than me—namely, et—being a certain way, I am not conscious in virtue of something other than me being conscious. Thus, I do not derive my consciousness from the consciousness of anything else, and so I am non-derivatively conscious. I do derive my consciousness from something else being a certain way, but when that something else is a trope of me, that's quite innocent. Thus, (2) is not an issue here.

Nor is (3), for the obvious reason that a fusion of et-type tropes, even if there is such a fusion (which I very much doubt), doesn't think. It's substances that think, and they think in virtue of having certain tropes. The tropes don't think, and neither do their fusions.

I don't think this is the whole story. If I were seriously defending this story, I wouldn't say that I have the trope et directly. I might say that I have the trope et as a trope of my humanity, where my humanity may well be the only trope I have directly (see the paper of mine here).

I don't know if the above story is true. I am a bit sceptical of the thinness and hyperplanarity, as it were, of the et tropes—they don't seem to me to be very natural. And I am not 100% sure I want to commit to tropes. But this version of perdurantism might be true.

Note, also, a neat thing. Normally the perdurantist needs to argue why perdurance is preferable to exdurance. But I do not think there is any plausible trope exdurantism paralleling this trope perdurantism.

Objection: The trope et is a part of me, so this devolves to a more standard perdurantism.

Response: Maybe in some sense my tropes are parts of me. But they are different sorts of parts from the kinds of parts that standard perdurantism invokes. For tropes depend, at least for their identity, on that which they are tropes of. But the whole is constructed out of the temporal parts on standard perdurantism. So trope perdurantism reverses the order of grounding.


Unknown said...

Hi, Professor Pruss—

I take it that the view you’re floating has at least this much in common with perdurantism: persisting objects are 4-D objects. But, there is a big difference; on your view, persisting objects lack proper temporal parts. I suspect this isn’t a form of perdurantism once you’ve given up proper temporal parts. Instead, I take it that it is a form of what Paul Daniels calls transdurantism in his dissertation (2014).

It looks like you’re going to have to give up one of the motivations for perdurantism, viz. its ability to make sense of how something has a temporary intrinsic property. Suppose that being bent is an intrinsic property, and that it is temporary in that something could have it at some times, but not others. The perdurantist can at least say that Lewis is bent because he has a proper temporal part that has the intrinsic property being bent. Granted, perduring Lewis only has the property derivatively in virtue of having a proper temporal part that has the property.

But think about the tropes. Are those properties intrinsic? I don’t think so, at least not on the following gloss of intrinsic: a property is intrinsic just in case an object has it solely in virtue of the way it is in itself. Transduring Lewis doesn’t have the property being bent solely in virtue of the way he is in himself; the story seems to involve something besides Lewis, viz. spacetime. If that’s right, it seems like you get the non-derivative having of properties, but they aren’t intrinsic.

Finally, it might end up being hard to make sense of Lewis’s age; I’m borrowing this from a paper by Kris McDaniel. Suppose that fundamental particles transdure. There’s good reason to believe that their lives are much, much longer than Lewis’s life. Suppose that Lewis is a sum of those fundamental particles, and let’s also suppose that things nether gain nor lose parts, for simplicity’s sake. The sum exists long before and long after it seems right to say that Lewis does. The perdurantist who believes in temporal parts can appeal to a 60 year slice of the sum and say that Lewis is identical to it. But the transdurantist can’t do this, since there are no proper temporal parts of the sum. So it seems like transdurantism gets the ages of objects wrong, but perdurantism doesn’t have this problem. Is there some way to get around this problem on your view?

Alexander R Pruss said...

1. If a temporary property is one that an object has at one time and that the object lacks at another, then perdurantism fails to do justice to the intuition, either. Bentness is intrinsic in the instantaneous temporal part and extrinsic in the worm; on the other hand, it is temporary in the worm but not in the temporal part. So there is no x and P such that P is a temporary intrinsic property of x.

2. I think the relevant times are internal times (personal times, if the substance is a person) rather than external times, so the possession of e_t may well be intrinsic. In fact, the possession of bentness at t might be intrinsic as well.

3. The age argument shows very nicely that if a particle is a temporally extended object, then we do not have particles as parts (since some would stick out of us), or at least not very many particles (maybe a few are sufficiently shortlived that they fit inside us).

This argument applies on any view on which we are four-dimensional. The perdurantist, though, can soften the counterintuitive consequences of this by saying that at least we have as parts temporal parts of particles. I can't say that. But note that the perdurantist has a cost here. She needs to say that fundamental particles are composite (being made up of temporal parts). And if she further thinks that wholes are posterior to parts, she has to say that fundamental particles are not ontologically fundamental.

That said, I have independent grounds to embrace the conclusion. For Aristotelian reasons, I take it that either (a) substances do not have parts, or (b) the parts of substances are identity-dependent on the substances they are a part of. (And indeed this is one of the motivations for not going for standard perdurance.)

On both Aristotelian options, one must hold that when a particle is accreted into a substance, the original particle ceases to exist. In case (a) there is no particle there at all--we are extended simples. (But the particle's accretion to the substance causes the substance to gain causal powers akin to those the particle had.) In case (b), a new but similar particle comes into existence, which is a part of the substance and depends on that substance for its identity (and conversely when it is excreted).

And on neither Aristotelian option is the age problem an issue.

Alexander R Pruss said...

And thanks for pointing me to Paul Daniels' work. It is good to know about.

I've held that I am probably a four-dimensional extended simple for a number of years. (Previously, I held that I was a three-dimensional extended simple.)

What makes the view of this post different from just saying I am a 4D extended simple is that like perdurantism, the current view explains change by positing a succession of distinct instantaneous entities, each of which is, of course, unchanging. The main difference is that the perdurantist's entities are more fundamental than the 4D whole, while my entities are modes of the 4D whole.

Unknown said...

Thanks for the responses. Those are helpful.

1. Here's another stab at what I think I was trying to get at. One might think that being bent is an intrinsic property; something has it in virtue of the way it is in itself. My thought was that the tropes don't capture the intrinsicality of being bent; they're like temporally-indexed properties. Something could not have that trope independently of times. The thought was that the perdurantist is in a better position here because she need not say that the property is temporally-indexed, or whatever. The stuff about having the property temporarily is a red-herring, I think. Does that worry make sense to you?--I don't intend it as an objection, but it might carry some weight for those who are taken in by the initial worry about intrinsicality as a motivation for perdurantism.

2. As for the internal times strategy and your second post, my worry is that, somehow, this divorces time and change. We need not appeal to time to make sense of how something changes; we need only appeal to internal time. That's super hand-wavey. Maybe you could help me see where I'm going wrong?

3. I've seen other folks note that, if fundamental particles are perdurers, they have proper temporal parts. And then they say that this is a cost to perdurantism. Is there supposed to be some problem here besides the issue about the relation between part and whole, viz. that if, say, the electron depends on its proper temporal parts, it is not ontologically fundamental?

The Aristotelian response to the age argument is pretty neat.
And using the succession of short-lived things to explain persistence is a good way to draw a connection to perdurantism; I hadn't thought about that. It might be enough of a way to maintain your view's being a form of perdurantism. (I don't suppose that much hangs on whether we call the view perdurantism or not, of course.)

Kruti Vekaria said...

Hi Dr. Pruss,

I'm just delving into metaphysics so I'm a bit new to all of this, but you said the standard perdurantist could avoid the problems you listed if they accept the "right kind of trope theory." But what trope theory are you supposing out of curiosity? Are you just supposing a bundle trope theory or something like a substratum + trope theory?

Alexander R Pruss said...

I meant: a trope theory that can accept everything I say. A bundle theorist might have trouble with the essential/accidental stuff. A substratum (bare or thick) + trope theory is better.