[UPDATED AND EXPANDED 26.06.10]
In a thread at Dr. Feser's blog, a discussion of how hylomorphism relates to time, and specifically Einsteinian relativity, recently prompted a new tangent about perdurantism. Perdurantism is, I must be frank, an old bête noire of mine.
One commenter there led off a reply to the mention of a perdurantist argument against Oderberg's endurantism by saying, "Hales perdurance notion of change is not compatible with A-T substance metaphysics, but it practically completely spells out a process metaphysics. It also seems much more resonant with our intuitive experience of the present than endurantism."
I replied: "Sigh. I have a very low opinion of perdurantism, to put it mildly."
And here's most of why.
1) It begs the question by saying an object's parts are, well… PARTS. Parts belong to whole and parts cannot belong to wholes unless the wholes actually exist. Ergo, one cannot refer to a part of a whole at time t if the whole does not also exist at t.
2) Perdurantism is more or less an embarrassed way of admitting what substantial metaphysics has always asserted, namely, that an existent's substance is not purely, nor wholly, physically quantifiable. What perdurantism latches onto is the fact that, in a materialistic spacetime manifold, no finite observer––nor any physically 'enmeshed' observer even infinite perceptual powers––can ever observe all of an existent's matter at one instant in time; ergo, no existent is materially wholly present at any instant. But this is just to admit that 'what a real thing is' (viz., its substantial essence) is not a material but an immaterial, and therefore nonquantifiable, reality. A thing's essence is what it is, perfectly, regardless how 'fragmented' its nonessential material components may be in the spacetime manifold. Hence, perdurantism really comes down––again, in an embarrassed but ultimately hollow way––to saying that, since none of an existent's spatiotemporal parts "all exist together at one instant," therefore those discrete parts are not essential to––not exhaustive of––the existent. But to make this move (viz., to distinguish between a thing's essential and non-essential parts while still speaking of THE THING ITSELF), is just to be a hylomorphist. As I wrote in a post nearly two years ago:
"Hylomorphism does not mean an object or thing is wholly and completely present in each part of itself, but only that each part of a thing is wholly and conjointly present to that thing's form as the integral substance of its material divisibility. The front of a train may exist in a different time-frame from the back of the train, as special relativity indicates, but this does not mean the train is only partly present in different time-frames. All it means, hylomorphically, is that the essence of a train formally unites the different sections of the train in different time-frames. All the parts, in every time-frame, are still under the formal power of the train as a substantial entity."
3) I find the notion of infinitely divisible "time slices" incoherent on its very face. For, if we slice finely enough, we are left with non-extended, infinitely thin time slices. But a stack of infinitely thin sheets of paper is itself infinitely shallow. As I wrote in a post a year or two ago:
"…[An idea] I got from David Oderberg's essay, ["Hylomorphic Dualism," is that] it is incoherent to say a thing's spatiotemporal structure is comprised of spaceless, timeless slices. In other words, offering two trillion totally worthless pennies to the cashier is no better or worse than offering only two. Since perdurantism denies there are substantial wholes which exist as wholes over multiple points of spacetime, it must also deny that any of the time slices "in" an "object" endure over any extended amount of spacetime. Ergo, each time slice is infinitely thin and infinitesimally brief. Unfortunately, however, stacking two trillion infinitely thin plates under your feet gets you no higher than stacking only two infinitely thin plates under them. Likewise, if I give you all my money for an infinitesimal amount of time, it really just means I do not give you my money. There is no coherent natural way to get spatiotemporally extended objects from spatiotemporally non-extended parts."
4) Consider also the most rudimentary elements of the Standard Model in physics. Some of the earliest components in the origin of the cosmos last on the order of 10^-43 sec. What room do we really have here for saying such an "object" has infinitely many parts in the span of so little time? For if we cut into that narrow window of happening, we have actually cut the happening into a wholly different phenomenon. The explosion and dissolution of leptons, for instance, include in their very nature to exist at a precise temporal instant, not at many arbitrary (and arbitrarily fictional, I might add) instants, so to scatter them over many instants is to destroy in their essential spatiotemporal "fragility." A lepton qua lepton is precisely transient and doesn't exist at a myriad of different times.
In any case, here is a link to all I seem to have penned at my blog with the word "perdurantism" in it: http://veniaminov.blogspot.com/search?q=perdurantism
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Some time later another commenter responded that my worry about "summing" infinitely many infinitely thin time slices isn't a problem for perdurantism, though my other objections he left unchallenged. He said that "if the parts are infinitely small, then you need infinitely many of them, that's all."
In response I said that I was careless in some of my comments, so I want to reiterate that 3a) the problem I have with infinitely small time-slices, and thus perdurantism as such, is not that "they're just so damned small!" but rather that such 'independent' parts are ontologically illicit in perdurantism. An infinitely small time slice has zero spatiotemporal extension, and therefore it does not exist for any amount of time.
1a) The other problem with these time slices, which I implied in my objection that perdurantism begs the question of wholes by focusing on PARTS, is that the parts have no more coherent existence in perdurantism than do the wholes. If integral wholes are a problem for the perdurantist, why are not sub-integral wholes (aka time slices) equally problematic? Otherwise, it's unparsimonious in the extreme. If I (my whole self) can't/don't exist all together at one time, and therefore endurantism is wrong, then none of my parts can/does exist altogether at one time, and therefore perdurantism is false. This is because each 'part' of me is a respectable whole in its own right, but allegedly the very idea of wholly present substantial 'wholes' is verboten for perdurantism. What decides how large or small a part is? There is nothing formally substantial about me or any of my time slices, so we can't meaningfully invoke either of them, if perdurantism is true. As such, perdurantism has nothing with which to articulate its own position.
5) Lastly, I should add that perdurantism is perhaps the only popular 'scientific' ontology that flagrantly violates the Scholastic razor (aka Ockham's razor). David Lewis's modal realism is equally flagrantly "hyper-ontic" and 'scientific' but, understandably, not as popular as perdurantism. Alas, such is academic whimsy.
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The beat goes on…
Later in the same thread, one of the same commenters replied:
"I don't see the problem. An infinitesimal value isn't really zero, so it's no worse than infinitesimally small points in space. And if single points in time (or space) were problematic, then endurantism wouldn't work either, because everything would only ever exist for an instantaneous, zero-length present moment. … I thought that it claimed you can't exist at one time because you in fact exist at multiple times, and therefore must be "spread out" across time, i.e. have temporal parts. Something could perdure for only a single moment, at least theoretically, I think. (But such an "instant" entity couldn't change, because it would have to last for at least two moments of time or more; you obviously do change, so for the perdurantist it follows that you couldn't exist for only one moment, but that's a historically contingent fact, not a metaphyiscal [sic] necessity.)
I do agree with your earlier point about this requiring a form to underlie all the "points" of time and explain what makes them parts of one thing. (Otherwise, the whole idea is rather, er, pointless.) And it doesn't help any with explaining the really tricky part of time, which is how our consciousness of it changes."
To which I replied, first:
"We're in a sort of Bonaventure-Aquinas cycle about the infinity of the created world. What I think we both agree on, which rather dissolves the technical disputes about infinite divisibility and ontic coherence, is that there must be SOMETHING of which the parts are… parts. In your quotation above, it begs the very same question: what do you really mean (as a rehearsed perdurantist) by "something"? There are no "somethings", only parts of fictitious whole-things. The perdurantist has no grounds for saying this 'something' is a distinct whole amidst a larger Humean-related 'whole' and as such has no grounds for saying this preferred something exists for an infinitesimal time."
He then replied:
"…the perdurantist objects, no, not everything is made up of parts; only changing things. An instantaneous part does not (cannot!) change, so it needs no further explanation. And I think that's OK, as far as it goes. Of course, it doesn't go very far; what makes a set of parts into a whole? Is it merely being adjacent somehow? The same question applies to what makes spatial parts into "one" thing? If perdurantism is an attempt to escape forms, then either everything is reduced to single, unconnected, atomic points (in time and space), or else the only "thing" is just the whole universe, here and there, now and then, all making up one big everything. … I guess we agree that it's another example of modern philosophy tying itself in knots to solve a problem that the ancients already solved, if only they knew it."
"I want to return to something you said which ties in to my latest comment: You said:"I don't see the problem. An infinitesimal value isn't really zero, so it's no worse than infinitesimally small points in space. And if single points in time (or space) were problematic, then endurantism wouldn't work either, because everything would only ever exist for an instantaneous, zero-length present moment."
This is a good point and I will only reply with two thoughts. 1) Maybe my thinking is just woolyheaded about infinitesimals in ontology, in which case, lead on, Magister. 2) If I am not fatally wooolyheaded, I would aver that single-point existence is not bad for endurantism at all. For the point is that there is a some-thing which "underlies" ('substat') each material entity's existence in contradistinction to the sensible features of that entity qua THAT entity. Instants versus substant, so to speak.
And, my woolyheadedness be damned, I would aver, once more, that the reason infinitesimal parts are illegitimate for perdurantism is any part is itself a kind of whole. Authentic perdurantism is a kind of stuttering ontology: "This, no, th-this is, no, no, th-th-this is the part, the part of the par-part of th-the whole that interests m-m-meeee." Any part that is not utterly zero is a genuine whole; and an ontology that posits wholes, of any size, is endurantism. Are my parts made of parts as well? If so, am I actually made of my parts or are my parts' parts made of 'me'?"
Some time passed and I remounted the horse, thus:
"Okay, let me try it this way.
If a time slice of me (M:ts1) has an infinitesimally small temporal extension, its spatial dimensions can just as easily be shrunken to infinitely small proportions. As such, according to perdurantism, 'I' can exist 'in' a ts with infinitesimally small spatiotemporal extension, which, when taken to its logical conclusions, means 'I' can exist in a simple mathematical point (M:ts^-∞): infinitely unextended. At that point (…), though, what sense does it make to claim that 'I', perduring 'in' M:ts^-∞, am in fact a material entity? Are ideal mathematical points material entities simpliciter?
Insofar as perdurantism takes for real what are in fact merely infinite abstract incisions in real existents, it dissolves into idealism. Just because I can 'find' an infinite number of sections in a cigarette or a candy bar, that doesn't entail the cigarette or candy bar are actually infinitely extended. Perdurantism is Zeno's paradox for physics nerds, and it's no coincidence that Aristotle opposed Zeno's paradox as an integral step in his substantialist ontology."