I am not identical with my body:

Assume I am a thing, which endures through time.

1) My body at time t has part P.
2) My body at time t1 does not have part P.
3) Therefore, by Leibniz's Law, my body at t is not identical with my body at t1.

This simple little argument shows that it cannot be the case that I am my body. It is also case with the brain, since it looses/acquires new parts also. Note that the magnitude of the part does not matter. And If you say a body minus one part is still a body, you run into something like the heap paradox. We then have three possible solutions: (1) I something other than my body and any part which constitutes it. (2) There is no identity over time. (3) Indiscernability of Identicals is false.

Scott wrote:While I happen to agree that you are not your body and I am not my body, I do not think the argument in the OP is sound. Not only is the poster before correct that the argument merely proves that your body changes, but also I think the premise is suspect. It assumes you don't change which I think is incorrect, and it may also be a fallacy of equivocation considering the word I may be very equivocal.

It proves something much more than that because it has implications. Leibniz's Law (Indiscernibility of Identicals) states that if two things are identical, they have the same properties (or that whatever is true of one is also true of the other). Now, if my body B at t has P whereas my body B1 at t1 does not have P, B and B1 are not the same thing. This is not merely a matter of changing, but of becoming literally a different thing. Now, as I said, we can either say that (1) I am not body, (2) there is no identity over time, or (3) Leibniz's Law is false. We don't want to accept either (2) or (3), so we should accept (1).

You say that I'm assuming I don't change, and that's correct. I can't be something that changes, since, again, I could not endure through time.

Take the following argument:

(1) If I change throughout time, then I am not the same thing over time.
(2) I am the same thing over time.
(3) Therefore, I do not change throughout time.

The self is metaphysically simple, that is, it is not made out of parts. Really, the only things, which, can undergo change are composite objects.

Scott wrote:You are mixing up my body at t with my body. Of course, X is not identical to Y if X is your body on Feb 26 2011 and Y is your body on Feb 26 2012. But neither the term your body on Feb 26 2011 nor your body at this very moment is synonymous nor identical with the term your body as the term your body unless specified otherwise refers to a 4-dimensional object of which both your body on Feb 26 2011 and your body at this very moment are a part.

I think you might have misunderstood why I think B and B1 are not identical. I'm not claiming that B and B1 are distinct bodies in virtue of one existing at a time the other doesn't. What I'm claiming is that if B1 on Feb 26 2012 has a part (or property) B hasn't on Feb 26 2011, they are not identical. It would be perfectly fine for an object to be itself at another point in time, but it could only do so if it consisted of the same parts/properties.

This makes more sense when we inquire to what a concrete particular body is in the first place. Well, a body (and any other concrete particular) is a set of parts and/or properties. But a set is identical with another set if and only if they both have the same members. So, if P is a member of the set B but is not a member of BI, B is not identical with B1.

About the self. I of course mean this in the sense of being a mind. A thing, which perceives representations as its own. So, yes, although 'I' can be used in many ways (as Wittgenstein noted), I have a specific use.

-- Updated February 27th, 2012, 12:59 am to add the following --

Belinda wrote:

The self is metaphysically simple, that is, it is not made out of parts. Really, the only things, which, can undergo change are composite objects.

Is this elemental self anatomical or physiological, or is it a psychological construct? There is not anything else it can be unless it is supernatural. Supernatural things cannot be proved to exist, because if they could be proved to exist they would be natural, not supernatural. Anyway, elements are not made out of parts and elements can undergo change by becoming compounded or mixed with other elements, and elements can also move around in space.

It is not even possible to find the self by introspection.

You say that I'm assuming I don't change, and that's correct. I can't be something that changes, since, again, I could not endure through time.

It is a mental substance. I'm not a Theist (I'm actually an Idealist), so for me it does not have any supernatural connotation. But even if it did, you are wrong to say that supernatural things cannot be proved to exist because they would be natural and not supernatural. This rests on the assumption that proof is strictly empirical. That disregards mathematics, logic, and a priori philosophy itself. Secondly, empirical investigations are always inductive, since no amount of experiments can confirm a natural law. For example, no matter how many times you drop a ball and it falls, it does not necessarily follow that it will fall the next time. As Hume showed, experience only tells us what is the case but not what must be the case.

Speaking of Hume, you falsely believe that the self is something to be perceived itself when you say, "It is not even possible to find the self by introspection". That is, you're looking for an impression or idea of a self. But this is just misunderstanding what a self is. A self is a thing which perceives, not a perception.

Belinda wrote:
Fhbradley wrote:

Speaking of Hume, you falsely believe that the self is something to be perceived itself when you say, "It is not even possible to find the self by introspection". That is, you're looking for an impression or idea of a self. But this is just misunderstanding what a self is. A self is a thing which perceives, not a perception.

AS you say I was indeed thinking of Hume.The self as subject, defined as a thing which perceives, is also what is up for discussion, besides the self as an anatomical or physiological construct. If the self is the thing which perceives, what of the changing flickering perceptions of gestalts such as the duck/ rabbit or the vase/ human profiles, or the old hag/ young woman? Also, what is it that is perceiving when we are examinng our idea of self: here we have the beginniong of a regress.
My self's attributes cannot be measured as it has no dimensions. My self as a mental construct can be measured by brain correlates but this is not what we are talking about.My self's attributes are also mental constructs but those also do not exist in space time. However even mental constructs however nonsensical have an existence as they are within the cycles of cause and effect. But we are taking about the sustantive existence of the self in space and time, not the self as mental construct.

How do optical illusions debunk a self? In fact, optical illusions debunk empiricism (which you adhere to), since otherwise, you could not interpret these sensory phenomenon as illusions! Hence the distinction between sensation and the intellect. As for what is perceiving when we are examining the idea of a self, this is a tricky question, because I'm not sure what you mean by 'idea'. Sure, the self can itself be an object for the self, but not in any concrete sense. If I'm "thinking about the self", that self, which, becomes an object for consciousness, is only an abstract idea, not the self itself. Also, there is no self in space and time (assuming space and time even exist!), since the self, at least within my definition, is non-spatial.

Scott wrote:Yes, but in a non-abstract sense everything is constantly changing and swapping parts, such as the water flowing away from a river, the electrons from my carpet being replaced by new ones, etc. Because of that, almost all our words refer to 4-dimensional patterns of things. 'My carpet' doesn't refer to a certain set of atoms and electrons; 'his river' doesn't refer to a specific cubic feet of water, and 'your body' doesn't refer to that which changes about it. That particular water in that amount may happen to be part of the river at a certain time but at another time it may not and the term my river refers to the river at both times in a 4-dimensional, relative way. Similarly, your body may refer to a mass that has long blond hair at one time and is bald at another. You may change in the way your body changes (i.e. an instance of your body has a property at a certain time that your body does not have at another time, even though both are actually your body), but the concept of you 4-dimensionally may be identical with itself and body in the way body is identical with itself. Baldness or hairiness cannot be a property of your body, but can only be a time-relative quality of the changing-over-time 4-dimensional concept that is 'your body'. You may change just like your body changes, but you may not change in the sense that 'you' are identical with itself even when used at different times.

First, I think the doctrine of temporal parts is untenable because it must appeal to an unknowable substratum. Where's the 'Descartes' behind all those parts? Where is 'river' behind all that water? We should not multiply entities beyond necessity. Secondly, you did not respond to my point about the nature of particulars, which refutes both the doctrine of temporal parts and the notion that a concrete particular can endure or persist over time if it changes its parts (note that a concrete particulars are composite objects. Essentially:

1) A concrete particular is a set of parts and properties.
2) Two sets are identical if and only if they contain the same members (that is, those parts and properties).
3) B is a concrete particular and B1 is a concrete particular.
4) B has a member a at t (say, my arm)
5) B1 does not have a member a at t1
6) Therefore, B is not identical with B1.

Of course, B could have endured through a time-series, but only if at those time-instants it had all the same members. So this is inconsistent with a temporal parts view of identity, since, a set cannot change its members and still be the same set.