Persons do not possess temporal parts.
Debate Rounds (4)
I shall be arguing in favor of the position that persons do not possess temporal parts - or, in slightly less technical terms, persons endure over time and do not perdure over time.
Definitions and Clarifcations
Person - very minimally defined, a subject of experience. The term "person" no undoubtedly means more than that but it also can't mean less than that.
Possess - to have as an attribute, knowledge, or skill. 
Temporal parts - are a concept used in contemporary metaphysics in the debate over the persistence of material objects. Objects typically have parts that exist in space—a human body, for example, has spatial parts like hands, feet, and legs. Some metaphysicians believe objects have temporal parts as well. A temporal part would thus be something like "the first year of a person's life", or "all of a table from between 10:00 a.m. on June 21, 1994 to 11:00 p.m. on July 23, 1996". 
Perdurance - Perdurantists believe that ordinary things like animals, boats and planets have temporal parts (things persist by ‘perduring'). 
Endurance - Endurantists believe that ordinary things do not have temporal parts; instead, things are wholly present whenever they exist (things persist by ‘enduring'). 
Round 1: For acceptance and/or adding clarifications.
Rounds 2 - 4: We present our specific cases.
All rounds: Have fun! :P
I'd also like to include one last clarification:
Purdurance: Terminology introduced by the 20th-century Australian philosopher Mark Johnston for an older contrast, and described by David Lewis in The Plurality of Worlds. Something perdures if and only if it persists by having different temporal parts, or stages, at different times, though no one part of it is wholly present at more than one time. It endures if and only if it persists by being wholly present at more than one time. Perdurance corresponds to the way a play is extended in time: Act I is not present when Act II is. The question then is whether it is better to think of ordinary objects as perduring or enduring.
Thanks to Vi_Veri for agreeing to debate this with me. I look forward to this being a learning experience.
In the following round I will present the "too many thinkers" argument against the doctrine that persons possess temporal parts.
I am inspired by arguments from Dean Zimmerman,  and Jim Stone. 
Am I PCP-present or PCP?
Assume that I have temporal parts for the following thought experiment:
Let's designate a temporal part/stage of me; call it PCP-present (where "present" designates this exact moment in time). PCP-present isn't me, however, because according to temporal parts metaphysicians I perdure over time and I, PCP, am just an aggregate of all my temporal parts. I have temporal parts that go way back further then PCP-present; in fact I have perdured for 22 some odd years. So, obviously, I, PCP, cannot be PCP-present. PCP-present is just the part of me that is extended over some specific time period called the present. Think about this, though - PCP-present is quite literally indistinguishable from me, PCP. PCP-present has all the same physical qualities, is thinking all the same thoughts, and feeling all the same emotions that I am yet he is not me. He is feeling happy that he gets to debate Vi_Veri just like I am. He is thinking that is going to be a tough debate just like I am. His stomach is full from just eating dinner just like mines is. There is a dull ache in his feet just like mines are. He's thinking "Man, I want to go play basketball and then play some Mass Effect 2" just like I am. He's thinking that he better hurry up and finish this debate round soon before time runs out just like I am. His brain chemistry is the exact same as mine. He somehow has my own exact DNA code as well! I think everybody gets the picture by now.
Somehow, PCP-present has every single quality in common with me in the present moment yet we are different. That means there are two different thinkers thinking all my thoughts, feeling all my feelings and looks and acts exactly as I do in this very moment. If we are indistinguishable in this sense then how do I know which one I am? Am I PCP-present or PCP? If I, PCP, think "I am a person" I think this thought truly. If PCP-present thinks the thought "I am person" he thinks it falsely because PCP-present is not a person; he's just a mere temporal part of a person. How can this be? We are both thinking the very same thought at the very same time with nothing to distinguish us yet PCP-present thinks the thought mistakenly and I, PCP, think it correctly. If this is the case how can it be that I can even tell the difference between me, PCP, and PCP-present? How do I know which one I am? Maybe "I" am actually PCP-present? I don't know - there's no way to tell. So, even if I was PCP-present I'd still think I was actually the person PCP because that is what PCP thinks. That seems like the height of delusion on PCP-present's part to actually think he is a person when he really isn't...but, if you think on it, if PCP-present has all the same properties as I do in this very moment then wouldn't that make him a person as well? So, wait, are there really two distinct, different people sitting here who share all their properties in common? This is the "too many thinkers" argument against persons possessing temporal parts. There are too many thinkers here to make sense of and try to fit into a coherent framework.
If you add the above considerations with these two very plausible assumptions:
1) I can differentiate myself from other thinkers.
2) Other persons have the same ontological status as I do (meaning other persons aren't fundamentally different than I am; they share the same nature with me that makes them count as a "person").
We now have good reasons to reject the thesis that persons possess temporal parts.
I look forward to Vi_Veri and Vi_Veri-present's next round! ;)
-------------------- Counter Arguments --------------------------------
First - physical beings have spatial parts. A person, for example, has arms, legs, hair, cells - the list could go on and the parts could get very minuscule or very large, but the being can be divided into parts. This is undisputed. What I will be arguing is that a person can be divided into temporal, or time related parts, due to our existence in the 4th dimension.
We begin with Einstein. This brilliant scientist proved to the world that time and space are essentially the same thing (this has been experimentally verified) . We call this "space-time". Through the special theory of relativity, I will show that human beings do in fact have temporal parts. I will also refute my opponent's "too many thinkers" argument.
Endurantists believe that only this instant in time exists - or presentism. The past is long gone and the future isn't here yet. Endurantists MUST believe in presentism because without it, they can't make the claim that a person is traveling throughout time as a whole single being. Relativity teaches us otherwise. Euclidean space says that time is constant and universal. This is the theory of time that an Endurantist must accept if they are to believe that a person endures through time with no temporal parts. Unfortunately Euclidean space was disproved by STR which states that there is no fact to the matter of what is the present. This creates a big problem for presentists - which in turn creates a big problem for endurantists - which then leads to a problem for the instigator. Because time is relative to the observer depending on which speed they are traveling (and gravity), then time becomes a measurable dimension. Because it is a measurable dimension, it can be divided into parts. Thus - temporal parts.
So now let us take the person of PCP and put him into prospective. PCP from birth to death is identified as one whole being. Picture PCP as a straight line through the fourth dimension. Birth------------Death When PCP says the word "I," he is referring to the entire picture of PCP. That is essentially what PCP is. When PCP says "I'm a person," he is referring to the big "I" - the whole picture of PCP. What makes PCP a person is his essential identity. Therefore, PCP from birth to death will always be PCP, but that does not mean that PCP's full length 4th dimension existence can not be divided into parts. During a slice of temporal part of PCP, he may be hungry. He could say, "I am hungry." By saying "I am hungry," PCP doesn't mean that he is always hungry. He is talking about a certain instant in time (particularly this slice of temporal time). If we go forward in time - to when PCP gets something to eat - he can say "I am not hungry." We understand, again, that he is talking about a particular moment in time - in other words, he is describing a particular part. It is like the difference between saying (again with the spatial definition) "I have a hand," and, "I have a body."
Now Pro says, " We are both thinking the very same thought at the very same time with nothing to distinguish us yet PCP-present thinks the thought mistakenly and I, PCP, think it correctly. If this is the case how can it be that I can even tell the difference between me, PCP, and PCP-present? How do I know which one I am?"
First of all - PCP present is referring to PCP as a whole when he says "I am a person." Now to clear up the whole "we are both thinking the very same thought at the very same time." What I infer that my opponent is saying is that if present PCP is a part of whole PCP, then the present thoughts of present PCP are also a part of whole PCP - and thus they are having the same thought twice - once in the present slice, and once as the whole. This is essentially the "too many thinkers" argument.
What is unfortunate about the "too many thinkers" argument is that it is a silly play on words. When one actually takes into perspective what a believer in temporal parts is saying, one would know to compare it to spatial parts (as we have been doing). Let me put it in a different format. Let me present to you the "too many grabbers" argument.
Say I go to grab a cup of water. First of all, my muscles are grabbing the cup of water. Secondly, my hand as a whole is grabbing the cup of water. THERE ARE TOO MANY GRABBERS. We have a problem!
Not really. Just as the part of the hand (the muscles) is grabbing the glass, present PCP is thinking his particular thought. And just as the muscles are a part of the hand that is, as a whole, grabbing the glass - PCP present is a part of the PCP that is, as a whole, thinking the particular thought - because it is a part of what the whole PCP is.
I look forward to PCP's counter argument! :)
Con has essentially two points to make:
1) The special relativity argument for temporal parts.
2) The refutation of the "too many thinkers" argument.
I'll tackle each in succession:
1) I agree that a endurantist is - or should be - committed to presentism. What I disagree with is Con's claim that presentism and STR are incompatible. Con's argument boiled down is, basically there is no such thing as "absolute time" as presentists assume (per STR) and since the "present" can only be relatively distinguished there is no reason for the special metaphysical privileging of the present moment which in case spells trouble for the endurantist who holds to presentism. I imagine that Con would take to this statement well: If one takes the science of STR seriously (and they should) and presentism truly conflicts with STR then so much the worse presentism. I aim to show how they are not incompatible and science, STR, gives us no reason to favor a theory of time that is compatible with perdurantism than over a theory of time that is compatible with endurantism.
2) Since the spatial parts analogies are particularly unmotivated we can now examine Con's alleged refutation of the "too many thinkers" argument. Con's argument is basically that when my temporal parts say "I" that denotes the person, me, as a whole; when I, PCP, say "I" am referring to myself. When a temporal part of me says "I" it's referring to the person it is a part of is what Con seems to advocating. Following this line of reasoning, therefore, if "I" both refer to same subject the "problem" with too many thinkers evaporates.
The problem with this is this raises several very difficult issues. What exactly is the word "I" supposed mean on a perdurantist account of persons? This seems like a linguistic trick - on the normal account the word "I" just refers to a subject when it is thinking about itself using first-personal terms. It's obvious my present temporal part as a first-person point of view because I, PCP, have a first-person point of view at present in virtue of PCP-present having that first-person point of view. If a temporal parts metaphysician denies the preceding sentence the jig is up because that is what a perdurantist is committed to. It's a self-referential word. With that in mind its not easy to to see why a PCP-present cannot be referring to itself when it thinks "I am hungry". As Jim Stone has aptly pointed out - word "I" plausibly just means "the thinker of this very thought".  If it doesn't it's hard to even make sense out of the claim that the word "I" doesn't mean that. If it doesn't does not the word "I' lose any sense of coherent reference? It makes no sense to have a something else do your first-personal thinking for you where "I" doesn't refer to itself. If that is the case then when PCP-present thinks "I am hungry" it is not referring to PCP - because, remember, I am an aggregate of temporal parts - it is referring to itself. This still leads us to major problems when we see that PCP-present can still think "I am a person" and it be false while I can think I am a person and it would be true. How can it be that "I" refers to two different thinkers when one is just a temporal part of the other?
And this highlights what is the problem with the "too many grabbers" argument. I suppose the analogy is suppose to be like just as the muscle of the hand are constitutive (i.e. they make up) the hand temporal parts are constitutive of the person. So just as when the muscles grab the cup of water the hand grabs the cup of water,similarly, when the temporal part(s) think "I am a person" the person also thinks "I am a person". The problem is all the muscles (including bones, I suppose) of a hand just are the hand. We are talking about an individual temporal part thinking something that is not true for itself but true for the person it is a part of. To make the analogy resemble the "too many thinkers" argument you'd have have a smaller amount of muscles then what constitutes the hand and the hand grabbing the cup of water. But if you show that then that is obviously just as an absurd conclusion as the conclusion of the "too many thinkers" argument.
Thankyou very much to Vi_Veri for being very lenient.
Con has essentially one point to make with regards to a consideration in favor of the doctrine of temporal parts and it centers around special relativity.
I'll tackle it in this round and have a little bit to say about spatial analogies with regards to temporal parts along the way:
I agree that a endurantist is - or should be - committed to presentism. What I disagree with is Con's claim that presentism and STR are incompatible. Con's argument boiled down is, basically there is no such thing as "absolute time" as presentists assume (per STR) and since the "present" can only be relatively distinguished there is no reason for the special metaphysical privileging of the present moment which in case spells trouble for the endurantist who holds to presentism. I imagine that Con would take to this statement well: If one takes the science of STR seriously (and they should) and presentism truly conflicts with STR then so much the worse for presentism. I aim to show how they are not incompatible and science, STR, gives us no reason to favor a theory of time that is compatible with perdurantism than over a theory of time that is compatible with endurantism.
I think all that a presentist has to do here in order to defend the compatibility of STR and presentism is reject the standard interpretation of the theory and accept a Neo-Lorentizian interpretation of STR.  The N-L interpretation of STR is empirically indistinguishable from the standard interpretation of STR but it does have an absolute frame of reference for time and space in which we can point to an objectively distinguished "present moment". The problem with the argument from STR to a specific theory of time is that scientific theories are always underdetermined.  It's not at all clear that just the scientific theory itself decides which theory of time one should hold to - one has to incorporate the philosophical considerations in for that theory of time are well. So if one holds that there are independent reasons for believing in presentism and holds to the N-L interpretation of STR there is no issue of incompatibility and Con's argument loses considerable force.
2 brief notes are warranted here, though:
1) Even if STR and presentism are incompatible that doesn't seem to be that big of a blow or much of a deciding factor in determining whether or not endurantism or perdurantism is true. For example, if one is committed to taking the finding of science seriously, the General and Special theories of relativity are anticipated to be replaced by theories of quantum gravity  and it is not at all clear that presentism and QG are incompatible. There doesn't seem to be much force in relying on an argument, even if it did work, that is likely based on a, as presently understood, false scientific theory.
2) The spatial analogies seem disanalogous when you think about them. The analogies are supposed to rely on the deliverances of Einstein where to quote Con "This brilliant scientist proved to the world that time and space are essentially the same thing (this has been experimentally verified)" and since time is like space (per that assumption) we can divide time into temporal parts just like we can divide space into spatial parts. There are problems with this, however. If time and space are essentially the same thing. If they are then how is that space 3 dimensions while time does not? Time seems to "pass" but space doesn't; time seems to to have an order whereas space doesn't. If these are essentially the same things then how is it that they can have disanalogous features? Something that is essentially the same things as another can't be disanalgous with the other thing it is being compared to.
My opponent combats STR with LET. LET requires for there to be an "undetectable aether." Because STR does not require this aether's existence (and because assumptions on space and time made by STR helped Einstein develop general relativity), LET is not a worthy competitor of STR. My opponent brings up that scientific theories are "underdetermined," but doesn't realize that it does not justify him using a theory that is disproved. STR destroyed the need for a single universal frame of reference (such as in presentism), and thus vanquished LET and it's luminiferious aether.
Einstein continued to destroy LET when he introduced the solution to the photoelectric effect. Showing that particles are wave like , Einstein proved that particles (and thus light) do not need a medium to travel through. LET's aether became obsolete.
Until my opponent can disfigure STR's concept of time and space, presentism has no scientific evidence to back it. This leaves my opponent's theory with no current empirical evidence he can hold on to. Einstein's experiments that proved space-time do place empirical evidence for perdurance - and thus temporal parts.
My opponent continues his arguments against STR by bringing up STR's apparent replacement: Quantum Gravity. What my opponent doesn't seem to understand is that QG is a theory that is under construction that will try to marry general relativity and quantum theory - not replace STR. The Principle of Relativity has been proven through experiment - I can not stress this enough to my opponent. The interpretation that PRO is looking at that would help QG prove presentism violates this Principle of Relativity. The argument presentists use to say that QG could prove presentism is CMC (constant mean curvature). This argument was brought up by Bradley Monton. Using my opponent's own source:
"Christian W�thrich (2010) takes Monton to task on a variety of both technical and non-technical grounds. He rightly questions Monton's claim that the CMC approach really is an approach to quantum gravity, in the same sense as string theory and loop quantum gravity. It is more of a piece of machinery that is used within a pre-existing approach (namely, the canonical approach)."  
Wuthrich shows that there is no presentism in quantum gravity.
As for pro's labeled number 2 argument against STR - Time "passes" just as space "passes." One can travel across space just as one can travel across time - and back again. It is as simple as that.
---- Too Many Thinkers Argument ----
My opponent has misconstrued my argument. What I am referring to when I say "when PCP says "I" is when PCP is talking about himself as a whole - the person he has been from birth to the present (and the future). When PCP is talking about himself during a certain slice of time, he says "I AM hungry" - indicating a present state. If he was referring to a slice of time that came before the moment in time in which he referenced a past occasion, he would say "I WAS hungry." This indicates a plotting - much like when someone says "Chicago is west of New York," PCP is saying "Being hungry is prior to this moment." The hungry piece of PCP (including trillions of other things that are happening to PCP during this time slice) is a part of the whole PCP - and this hungry PCP slice can have the property of the thought "I'm hungry." This does not indicate that there are too many thinkers, or that PCP is constantly referring to his whole self when he says "I." He is only referring to his whole self when he speaks of himself as a whole - when he says "I am PCP." But again, this is a slice of himself making a reference to his whole self.
---- Too Many Grabbers Argument ----
The muscles are a PART of the hand - just as a time slice of PCP is a PART of the whole PCP. Let me use another example for my opponent. Let us introduce the "too many digesters" problem. The stomach digests the food PCP eats. PCP's body holds his stomach which does this digesting. Thus because his stomach is a part of his body, this must conclude (using PCP's logic) that the body is also digesting (just as PCP whole is thinking "I'm hungry" when PCP time slice X is thinking "I'm Hungry.") We can see that this is trivial. The stomach is doing the digesting and it is only a part of the body that houses it. PCP time slice X is saying "I'm Hungry" and it is only a part of the whole PCP that houses it.
THIS DEBATE IS NOT OVER - ANOTHER 1 ROUND DEBATE WILL BE USED TO CONTINUE ROUND 3. THE LINK TO ROUND THREE WILL BE PROVIDED IN THE COMMENTS SECTION AND THE TOURNAMENT FORUM THREAD.
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