OBS: Even though it may be that I feel as though I am the same person as I were yesterday, that might simply be an illusion created by the neurological conditions of the body, which are the memories I/we hold. — Lionino

We are constantly changing, all the cells that constitute our bodies replaced every seven or so years according to some accounts. On the other hand, are we not distinguishable as the entities that undergo those changes?

e are constantly changing, all the cells that constitute our bodies replaced every seven or so years according to some accounts. On the other hand, are we not distinguishable as the entities that undergo those changes? — Janus

I was making this point to my wife yesterday. Persistence overnight might be fairly easy to deal with but me now is my e when I was nine via persistence of self? Seems utterly absurd. But I am clearly the same person so wtf haha

:ok:

My intuition is the we are a brief flash of light in the infinite darkness. I’m certainly not the same entity I was 20, 30, 50 years ago. I would need a substantive reason to accept some permanent substance/consciousness that persists across the ages, above and beyond personal identity. And even if it does, my next question would be how does it matter in terms of how we live? How do we get from this to reincarnation or consequences for choices? Or some other cosmology and metaphysics which seeks to exploit this murky model?

And even if it does, my next question would be how does it matter in terms of how we live? — Tom Storm

Parfit? Is that you? :nerd:

Call me Derek.

On the other hand, are we not distinguishable as the entities that undergo those changes? — Janus

The issue of identifiying something as that which undergoes change is for me a very deep issue that involves, among other things, mereology and semantics.
Because of that, I summon Theseus' ship. I ask you: is it the same ship?

I’m certainly not the same entity I was 20, 30, 50 years ago. I would need a substantive reason to accept some permanent substance/consciousness that persists across the ages, above and beyond personal identity. — Tom Storm

Right. So let's say you are not the same entity as 10 years ago. {That entity from before} and {you now} are separate. We can agree that that entity from 10 years ago is no longer anywhere, it is dead or non-existent. But what stops us from extrapolating those years to days and then to minutes. Are we dying every living second? To quote OP: "what reason do I have to believe in the maintenance of the self as opposed to its constant creation and subsequent destruction and replacement by another self?".

what reason do I have to believe in the maintenance of the self as opposed to its constant creation and subsequent destruction and replacement by another self?". — Lionino

I guess my response is another question- What reason should we care about that question? What experiences are you having where this is important?

I guess my response is another question- What reason should we care about that question? What experiences are you having where this is important? — Tom Storm

If you are not interested in discussing philosophy, I suggest going to Netflix instead.

That is a philosophical response. Pragamatism. Read more and try to think before you get lost in your own baggage.

"Pragamatism" has nothing to do with asking "who cares?" questions. No pragmatist says "stop researching" to theoretical physicists and asks them to become engineers instead. Stop pretending to know about a position you cannot even spell.

Because of that, I summon Theseus' ship. I ask you: is it the same ship? — Lionino

I don't think the same criteria for identity that apply to self-organizing systems such as biological organisms are relevant in the case of ships.

A relevant strip from Existential Comics.

Nice!

I don't think the same criteria for identity that apply to self-organizing systems such as biological organisms are relevant in the case of ships. — Janus

Why is that, if we are both physicalists?
And if it is a relevant part of your argument, I also wonder what defines self-organizing and how it makes something persist through time. Is the a wooden ship also not self-organizing insofar as the wooden planks move and twitch and compress and crack around to make room for the contraction and expansion that is caused by the temperature fluctuations?

A relevant strip from Existential Comics. — wonderer1

Amazing comic. It really captures the spirit of the thread, though maybe for narrative reasons it stops short of dying at every (micro-)second and instead keeps it for everytime sleep happens.

If all the cells in our bodies, in organisms generally, contain a unique DNA sequence that defines them then that is different than the 'ship of Theseus'. It is also a matter of metabolism. Look up 'self-organization' and you will see why it does not apply to ships or to anything other than organisms..

I just did skimmed through it, through this link. The definition given here would not exclude the wooden ship from being self-organising, as even sand in a dune would be self-organising.

If all the cells in our bodies, in organisms generally, contain a unique DNA sequence that defines them then that is different than the 'ship of Theseus' — Janus

Not all cells of our body have DNA, such as red blood cells. And some cells have different DNA, such as haploid cells. DNA expression is also different depending on the tissue you are taking the cell from.
DNA can't be used as the essence of a human being, otherwise two perfect twins would be the same person, and Hisashi Ouchi would be a different person after the radiation blast that destroyed the genetic content of the cells in his body, but I doubt that you, or anyone defending personal identity, would agree to that.

I had in mind self-regulation, homeostasis and metabolism, so my point holds. Also identical twins are not the same person because they do not inhabit the same space or have the same experiences.

You're right about DNA; it was careless of me to say "all cells...", although I find it implausible that all the DNA in his body was destroyed: do you have a reference for this claim?

I had in mind self-regulation, homeostasis and metabolism, so my point holds — Janus

And how is metabolism a metaphysically important process while the wooden planks shifting around is not? What makes it special from all the other processes in nature?

Also identical twins are not the same person because they do not inhabit the same space or have the same experiences. — Janus

Right, so then DNA is not the deciding factor then.

And how is metabolism a metaphysically important process while the wooden planks shifting around is not? What makes it special from all the other processes in nature? — Lionino

Metabolism and homeostasis are internally regulated. Another point is that the ship of Theseus could be considered to be the same ship or a different ship depending on your perspective, on what criteria you accept. Think about two examples of the same model of motor vehicle; are they the same or not?

Also identical twins are not the same person because they do not inhabit the same space or have the same experiences.
— Janus

Right, so then DNA is not the deciding factor then. — Lionino

Identical twins do not have the same DNA according to some sources. Do a search if you don't believe me. In any case I didn't claim that DNA is the only criterion for determining identity. Throughout your life you have a unique set of experiences. Even if identical twins were exactly the same at birth, divergence from that sameness begins immediately simply on account of them inhabiting different regions of space and experiencing different things through time.

In the third metaphysical meditation of Descartes — Lionino

Is this (.pdf) the one you're referring to? In particular, this passage:

All that is here required, therefore, is that I interrogate myself to discover whether I possess any power by means of which I can bring it about that I, who now am, shall exist a moment afterward: for, since I am merely a thinking thing (or since, at least, the precise question, in the meantime, is only of that part of myself), if such a power resided in me, I should, without doubt, be conscious of it; but I am conscious of no such power, and thereby I manifestly know that I am dependent upon some being different from myself

Yep, this excerpt specifically:

And though I were to suppose that I always was as I now am, I should not, on this ground, escape the force of these reasonings, since it would not follow, even on this supposition, that no author of my existence needed to be sought after. For the whole time of my life may be divided into an infinity of parts, each of which is in no way dependent on any other; and, accordingly, because I was in existence a short time ago, it does not follow that I must now exist, unless in this moment some cause create me anew as it were, that is, conserve me. In truth, it is perfectly clear and evident to all who will attentively consider the nature of duration, that the conservation of a substance, in each moment of its duration, requires the same power and act that would be necessary to create it, supposing it were not yet in existence; so that it is manifestly a dictate of the natural light that conservation and creation differ merely in respect of our mode of thinking and not in reality. All that is here required, therefore, is that I interrogate myself to discover whether I possess any power by means of which I can bring it about that I, who now am, shall exist a moment afterward: for, since I am merely a thinking thing (or since, at least, the precise question, in the meantime, is only of that part of myself), if such a power resided in me, I should, without doubt, be conscious of it; but I am conscious of no such power, and thereby I manifestly know that I am dependent upon some being different from myself.

We are not only parts, we are relationships between parts. The parts that make up us are not simply aggregated, but also have functions around a directing teleology.

Probably what we call soul (or that "I" that endures through all my representations) is nothing more than a relationship that endures through constituent parts that possess functions.

What relationships? If by relationship you mean the differences between them, I don't see how that factors into identity, since a carbon and a helium are different not in the relationship of their parts but in the number of parts. If by relationship you mean interaction; in a physicalist worldview every interaction is mediated by a physical mean, so that relationship itself would also be a part.

I have updated the OP to specify what I am looking for.

This is also one of the primary sources of Descartes' ontological argument, is it not? That because he is able to conceive of such a perfect being as God, then it is inconceivable that this God could not exist, as non-existence would be an imperfection. (It was just about this argument that Kant denied that existence was a predicate.)

Even though it may be that I feel as though I am the same person as I were yesterday, that might simply be an illusion created by the neurological conditions of the body, which are the memories I/we hold. — Lionino

I'd treat that question without reference to Descartes, as it is really being dealt with in a way that is quite alien to Descartes' line of argument, which is predicated on the indubitable reality of God and of the soul as 'res cogitans' and as having been created by God. (That said, again, it is just the kind of metaphysical argument that Kant objects to, on the basis of the absence of warrant for such claims, as distinct from religious sentiment.)

But leaving Descartes aside, the problem you're raising is one of agency, isn't it? That there is or isn't an agent who persists through time, such that he or she sets in motion acts that they will then reap the consequences of at some time in the future. The sense in which this agent is or is not the same from one moment to the next, is the point at issue.

This conundrum is also associated with the Ship of Theseus dilemma, which concerns an imaginary ship whose parts are replaced so often as to result in a wholly new vessel, and whether this is the same or a different ship at that point.

I feel that the argument that the agent is illusory must fail at the first step, as illusions are suffered by conscious agents, who mistake one thing for another.

What relationships? — Lionino

Like synapse between neurons.

This is also one of the primary sources of Descartes' ontological argument, is it not? That because he is able to conceive of such a perfect being as God, then it is inconceivable that this God could not exist, as non-existence would be an imperfection. — Wayfarer

If you are asking whether the Third Meditation is the source for one of his ontological arguments, yes, you can find it there. The Meditation itself is titled "That God exists". And though I don't see his proof as being phrased quite like you did (in fact it does not involve perfection as imagined but the causal origin of perfections he finds in himself), it is something along those lines we can say.

That there is or isn't an agent who persists through time, such that he or she sets in motion acts that they will then reap the consequences of at some time in the future. The sense in which this agent is or is not the same from one moment to the next, is the point at issue. — Wayfarer

Yes.

I feel that the argument that the agent is illusory must fail at the first step, as illusions are suffered by conscious agents, who mistake one thing for another. — Wayfarer

I was not quite arguing that the agent is illusory. I think that cogitō ergo sum is perfectly valid and even essential if we are discussing consciousness and personal identity. What I am putting in question is whether the agent at time t is the same as the agent that perfectly proceeds that one temporally and spatially in time t+1.

Like synapse between neurons. — JuanZu

That would be a part of the whole as it is physical.

What I am putting in question is whether the agent at time t is the same as the agent that perfectly proceeds that one temporally and spatially in time t+1. — Lionino

Does it have to be, to qualify as 'an agent'? Something can change continually and still maintain an identity, can't it? In fact, isn't that what every compound being is doing?

If Buddhists are asked whether the person who is born as a consequence of past karma is the same as the person in the previous existence that generated said karma, the answer you'll often get is, not the same person, but also not different. Identity is like that.

That would be a part of the whole as it is physica — Lionino

If one system belongs to another it does not imply equality between the identities of each system. For example, a living system may seek survival and reproduction; But, although the living system belongs to the solar system, we cannot say that the solar system seeks to reproduce and survive.