tag:blogger.com,1999:blog-3891434218564545511.post3175694493206687660..comments2024-03-28T19:56:42.305-05:00Comments on Alexander Pruss's Blog: ParthoodAlexander R Prusshttp://www.blogger.com/profile/05989277655934827117noreply@blogger.comBlogger15125tag:blogger.com,1999:blog-3891434218564545511.post-48176253232955635942009-10-07T09:36:11.654-05:002009-10-07T09:36:11.654-05:001. The problem of identity over time and change in...1. The problem of identity over time and change in properties is the problem of temporary intrinsics. There are different ways of handling it. One is presentism. Another, which is what I'd like to do, is some variant on time-indexing of predicates. Once we time-index our predicates Leibniz's law holds without any problems.<br /><br />2. Actually, I don't think that the kind of change where everything outside a part disappears happens very often. Consider everyday cases. You lose a bit of skin. But before you lost the bit of skin, the complement of the bit of skin wasn't a part. Not every collection of parts is a part. This goes against mereology, but we are talking of non-mereological parthood here.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-71037764364332614002009-10-07T08:36:35.282-05:002009-10-07T08:36:35.282-05:00"We need to talk of the time at which F is co..."We need to talk of the time at which F is constituted by A+B+C. Thus, at one time F is constituted by A+B+C and at another by C."<br /><br />Oh, of course. The way to do that is:<br /><br />1. F=A+B+C | t1<br />2. F=C | t2<br />3. c(F, A+B+C) | t1<br />4. c(f, C) | t2<br /><br />(You may be familiar with this same sort of thing in modal logic with respect to possible worlds.)<br /><br />And then identity laws would all operate within a fixed timeframe:<br /><br />\-/t,x,y (x=y | t) <-> (y=x | t)<br />\-/t,x,y,z {(x=y | t) & (x=z | t)} -> (y=z |t)<br /><br />And so on. And then all of this stuff goes away. The question <i>then</i> becomes how to formalize the concept of identity over time, but I think that pretty clearly deserved its own special rules all along. It can't be the same "=" as in the identity of indiscernibles, because the things are in fact discernible (again, you could easily tell the difference between me now and my teenage self; the same is presumably true of my this-world self and most or all of my other-possible-world selves). I dunno necessarily how to do this or which concomitant rules should apply, but you yourself admit that the other system is untenable:<br /><br />"I think the problem may occur in any case in which an object F has a proper part P such that F can lose all the parts outside of P"<br /><br />In other words, there's a problem every time anything changes physically? (Because, after all, this is just as bad when you <i>add</i> parts as when you take them away.) Things change physically literally all the time, so I can't imagine that a system that's incapable of describing this is a very useful system.Elihttps://www.blogger.com/profile/03543293341085230171noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-49601694101431289242009-10-06T23:15:18.705-05:002009-10-06T23:15:18.705-05:00Thanks! I hadn't seen that argument. On a qu...Thanks! I hadn't seen that argument. On a quick skim, I think the simplicity argument is quite different. For one, it only works for persons. For another, it assumes, I think incorrectly, that "part of" is used univocally between mereological and non-mereological cases.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-43414047218474771502009-10-06T20:46:16.038-05:002009-10-06T20:46:16.038-05:00Very interesting... E.J. Lowe has an argument in h...Very interesting... E.J. Lowe has an argument in his new book 'Personal Agency', which I think he calls the "simplicity argument" (it is about 1/2 way thru the book)which is similar to this one you are making...He argues that persons are 'simple.' Although I cannot recall the exact arguement, so to avoid botching it I will leave it at that.Andrew Jaegerhttps://www.blogger.com/profile/06478566939092309059noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-40655012435009681712009-10-06T19:34:42.158-05:002009-10-06T19:34:42.158-05:00We need to talk of the time at which F is constitu...We need to talk of the time at which F is constituted by A+B+C. Thus, at one time F is constituted by A+B+C and at another by C. <br /><br />I think the problem may occur in any case in which an object F has a proper part P such that F can lose all the parts outside of P, being left with P, and its subparts, as the only part. (We don't need P to be a simple part, as in my formulation in the post.) For then P either is or is not a part of F. It would be weird if it ceased to be a part of F simply because the other parts disappeared. So, it seems, it is a part of F. But it's not identical with F. So, by a plausible criterion of proper parthood it's a proper part--it's a part of F that isn't F. But it's an odd proper part, however, because there is nothing outside it that's in F.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-19054268395142876232009-10-06T16:15:55.595-05:002009-10-06T16:15:55.595-05:00Well, okay, and it's also worth pointing out b...Well, okay, and it's also worth pointing out before we continue that this would be just as contradictory if Fred were just B+C at t2, so long as A+B+C != B+C. So I'm also not sure what the one-part condition brings to the situation.Elihttps://www.blogger.com/profile/03543293341085230171noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-32806347565411106002009-10-06T16:10:40.638-05:002009-10-06T16:10:40.638-05:00Oh, good - there is already a word for that. I ma...Oh, good - there is already a word for that. I may have to go do some research (care to point me somewhere?), but it sort of seems like that causes an even bigger problem.<br /><br />If I'm following this, the mug is never identical to either its body or its body-plus-handle, but it is at various points in time <i>constituted of</i> just its body and its body-plus-handle. And likewise Fred can be constituted of any number of combinations of limbs and organs and so on without ever being any of those combinations. Right?<br /><br />But then in both of these cases, what does identity add to the situation? How does it even enter in? I can see maybe how Fred could be one identical thing the whole time if that thing is nonphysical, because then Fred's identity and his constitution are distinct. But the mug? I'm stumped on that one.<br /><br />Anyway, I'm not sure this resolves the problem. Your original argument went (roughly):<br /><br />1. F(t1) = F(t2) ("Fred at t1 is equal to Fred at t2")<br />2. F(t1) = A+B+C (etc.)<br />3. F(t2) = C<br />4. C != A+B+C<br />.: F(t1) = C<br />.: X<br /><br />But then why can't I say:<br /><br />1. F(t1) = F(t2)<br />2. c(F[t1], A+B+C) ("Fred at t1 is constituted of A+B+C")<br />3. c(F[t2], C)<br />4. C != A+B+C<br />.: c(F[t1], C)<br />.: X<br /><br />Unless "being constituted of x" isn't a predicate...? I have to say, I'm a bit at sea on this one.Elihttps://www.blogger.com/profile/03543293341085230171noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-50858304068390782472009-10-06T15:54:09.230-05:002009-10-06T15:54:09.230-05:00The standard move is to distinguish constitution f...The standard move is to distinguish constitution from identity. The mug is not identical with what was a part of itself. Rather, that part constitutes the mug. What is weird is that in this case there are no parts besides that one.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-17146731691109387062009-10-06T14:54:08.358-05:002009-10-06T14:54:08.358-05:00Right, that's just what I'm arguing agains...Right, that's just what I'm arguing against. I understand the formal line of reasoning, but it doesn't make sense to me to carry equality across times like that - I mean, I'm the same person now as I was ten years ago, but that doesn't mean that Liebniz's laws all apply to my current and teenage self.<br /><br />So, for another example, if I have a mug with a handle and the handle falls off...how am I supposed to interpret that? It's still the same mug, and it's now identical to just one of its pieces, but surely the handle was part of that mug beforehand. I guess you could say that it really is a different mug, but (a) I don't believe that and (b) then you have a mysterious special case when it comes to living things (possibly only people?). (Although actually that may not be so mysterious for someone who believes in souls.)Elihttps://www.blogger.com/profile/03543293341085230171noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-3882677168732072732009-10-06T14:43:40.241-05:002009-10-06T14:43:40.241-05:00Well, after losing all but one of the parts, he ha...Well, after losing all but one of the parts, he has only one part left. But it does not follow that he is identical with that part. If he were identical with that part, absurdity would follow. (Let's say at t0 he consists of A, B and C. Then A and B are destroyed, and only C is left at t1. Now, C-at-t1 = Fred-at-t1. C-at-t1 = C-at-t0. Therefore, by symmetry and transitivity of identity, C-at-t0 = Fred-at-t1. But Fred-at-t1 = Fred-at-t0. So, C-at-t0 = Fred-at-t0. And that's absurd.)Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-85775593453812762882009-10-06T14:39:24.280-05:002009-10-06T14:39:24.280-05:00Uh: "Suppose Fred, thus, loses all but one of...Uh: "Suppose Fred, thus, loses all but one of his parts. The remaining part is not identical with Fred—if it were identical with Fred, then prior to the loss of the other parts, Fred would have been identical with a proper part of himself."<br /><br />So Fred, after losing all but one part, is identical to just that part, from which you say that Fred "prior to the loss of the other parts" would also have been identical to just part A. Unless I'm misreading that?Elihttps://www.blogger.com/profile/03543293341085230171noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-89172950325506110432009-10-06T08:57:14.344-05:002009-10-06T08:57:14.344-05:00Sorry, the link was cut off. Try
alexanderpruss.b...Sorry, the link was cut off. Try<br /><br />alexanderpruss.blogspot.com/2008/01/parts.html<br /><br />(Alex, you may want to link it in the original post?)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-9703126291160602362009-10-06T08:54:26.526-05:002009-10-06T08:54:26.526-05:00Is this the other post that you're referring t...Is this the other post that you're referring to?<br /><br />http://alexanderpruss.blogspot.com/2008/01/parts.htmlAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-13919643867948783862009-10-06T08:41:35.031-05:002009-10-06T08:41:35.031-05:00I am not clear where I make this inference.I am not clear where I make this inference.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-27546969183856415362009-10-06T08:17:58.074-05:002009-10-06T08:17:58.074-05:00I dunno, I don't think it's a valid infere...I dunno, I don't think it's a valid inference from "this part is now the entirety of Fred (or whatever)" to "this part was always the entirety of Fred (or whatever)." I guess <i>maybe</i> you could pull that off in the case of people, but it doesn't work with inanimate objects, right?Elihttps://www.blogger.com/profile/03543293341085230171noreply@blogger.com