It is rather hard to see how "a cup exists only if there exists some X such that X is being seen or used as a cup" counts as scientific realism. — Banno

I explained it quite clearly in that post:

P1. A cup exists if and only if there exists some X such that X is a cup
P2. For all X, X is a cup only if X is being seen or used as a cup
C1. Therefore, a cup exists only if there exists some X such that X is being seen or used as a cup

Much like a king exists only if there exists some X such that X is [insert necessary social conditions here].

Do you believe that the argument is invalid, or do you reject one or both premises?

This has nothing to do with scientific realism, which only claims that the entities described by our scientific theories (e.g. the particles of the Standard Model) exist mind-independently (and behave as our models say they do).

Science says nothing about what it means to be a king or what it means to be a cup.

There's a reason that a "brain transplant" is also called a "whole-body transplant".

https://en.wikipedia.org/wiki/Brain_transplant

A brain transplant or whole-body transplant is a procedure in which the brain of one organism is transplanted into the body of another organism ... Theoretically, a person with complete organ failure could be given a new and functional body while keeping their own personality, memories, and consciousness through such a procedure.

I think this is the proper way to understand it.

I doubt she remembers anything. She’d have to form new memories. — NOS4A2

The brain has all the connections it had before it was removed from your body, so she will have your memories.

And I think that's absurd. It's not the case that Jane forgets her life and remembers yours; it's the case that Jane is dead and you're alive in her body.

You cut it in half. — NOS4A2

Yes, and in doing so it became two organisms, such as what happens naturally with some worms.

So how did you as a person die if both halves of your brain survived and were placed in two different heads? — NOS4A2

I can't be a single person in two disconnected bodies with two disconnected brains, and neither half is somehow privileged such that one is me and the other isn't. So it must be that neither is me. Therefore I'm dead.

I just don’t see how I would die if I was still alive after such a procedure. — NOS4A2

You wouldn't still be alive, you'd be dead. The body would still be alive, but the body isn't you. The body now belongs to someone else (the person whose brain replaced yours).

I've never been a brain. My memories and personality have only ever related to a certain organism. — NOS4A2

That doesn't answer my question. Jane's brain is removed and replaced with yours. According to you, it's still Jane. But given that memories are stored in the brain, it would then follow that Jane no longer has her (original) memories and instead has yours. So she remembers growing up as a boy named [your name] rather than as a girl named Jane.

I would remain as one organism, except I'd be one that's been cut in half. So I guess I'd have to choose both sides as me. — NOS4A2

But there are two unconnected bodies. How can they be one organism?

How would you die? Split-brain patients can live through such a procedure. — NOS4A2

"Split brain" patients aren't fully split. They are still joined at the stem. It's only the connection between the hemispheres that is removed.

I wouldn't because it would be extremely painful and debilitating. I would choose death before that. But if I did I don't think I'd be numerically identical to someone else. — NOS4A2

In this scenario it isn't extremely painful and debilitating. We're advanced enough that it's like a kidney transplant.

But my point is that it would be death, so it's not a choice between living (in pain) or dying; it's a choice between dying of brain cancer or dying of brain extraction-and-destruction, i.e. you're opting for euthanasia.

The body that's kept alive by a new brain just ain't you.

What if they could upload your consciousness and store it until the new body is ready? — frank

An upload is just a copy, it's not me. It's not like there's some physical substance that is literally removed from my brain and placed on a computer for safekeeping.

I'm curious; let's assume that brain transplants are possible and easy and that you have been diagnosed with terminal brain cancer. Would you accept a brain transplant as a cure (with your diseased brain being destroyed)?

Because I certainly wouldn't. I understand that this would mean my death.

I would be deceased. Jane would identify as Jane because it is Jane that is still surviving, still alive. I say this because one’s person’s body, via the immune system, would reject the other’s. I suspect that it would be Jane’s immune system rejecting my tissue, meaning my tissue is foreign, ie. not of the person. — NOS4A2

So, for you, a brain transplant is a memory and personality transplant? Jane receives your brain and with it loses her memories and personality but gains yours in their place?

So long as the survival of the organism or animal is maintained I remain the same organism or animal. — NOS4A2

What counts as an organism?

We've mentioned before that there are five "vital" organs; brain, heart, lungs, liver, and kidneys. At the very least we both appear to accept that we can replace the heart and still be the same person, replace the lungs and still be the same person, replace the liver and still be the same person, and replace the kidneys and still be the same person.

So let's say we separate your body into two, one part containing the brain, liver, and kidneys, and another part containing the heart and lungs. Each part's missing organs are replaced with artificial alternatives, sufficient to keep them all alive.

Are there two living organisms? Which one are you? I say the one with the brain.

If we could split your brain, put one half in body A, the other half in body B, where is your location as a person? — NOS4A2

I don't think either would be me. I'd be dead (even if the rest of my body is kept alive by machines), and there'd be two new people (assuming that half a brain is capable of supporting a sufficient level of consciousness).

Are you identifying the brain as Michael, or just the contents of that brain? — Hanover

I'm undecided. I don't know whether consciousness is reducible to neurological activity or if it's some (non-physical?) supervenient phenomenon.

I am only explaining that a brain transplant is unlike a heart transplant. I can replace my heart with another's but I cannot replace my brain with another's.

The brain in the jar is you if it contains your thoughts, which is why a vegetative brain is no different than you arm. Your essence isn't the brain. It's what the brain happens to be storing, which means you could be you in someone else's brain or on a USB drive. — Hanover

I don't think that's quite right. There's a difference between a working clock and a broken clock, but it's not like the working clock has some additional entity that can be taken from it and added to a different clock; it's just the case that a different clock can be made to behave in the exact same type of way.

Brains are perhaps just very complicated clocks. I am a specific (living) brain. Any other brain made to behave in the exact same type of way is a different token individual.

A → B means B or not A

If I punch you then you will cry does not mean you will cry or I won't punch you.

There's no logical mistake? It's just the case that "if ... then ..." in ordinary English doesn't mean what "→" means in propositional logic.

Michael, the argument is simply this:

If it is raining then it is not raining.
Therefore, it is not raining.

Who in there right mind would conclude the conclusion from the premises in a conversational setting? — NotAristotle

They probably wouldn't, because the grammar of ordinary language does not follow the rules of propositional logic.

In propositional logic, the following is a valid argument (specifically, it's a tautology):

P → ¬P
∴ ¬P

I am referring to the "it is raining" example; the conclusion in that argument appears to be a logical leap. I get that the argument is formally valid, that's the entire point - while formally valid, the conclusion does not appear to "follow." — NotAristotle

If it is raining then it is not raining
Therefore, either it is not raining or it is not raining
Therefore, it is not raining
It is raining
Therefore, it is not raining

Or more simply:

It is not raining
It is raining
Therefore, it is not raining

Still, it also appears that the conclusion is an unwarranted logical leap from the premises, so that is why I think there might be room to argue that the argument is not valid according to some informal definition of logical validity. That is to say, the conclusion doesn't follow or doesn't lead to the conclusion. I understand that this is not the definition of validity formally speaking. — NotAristotle

The conclusion logically follows, as has been explained many times.

P → ¬P
∴ ¬P ∨ ¬P
∴ ¬P
P
∴ ¬P

Or more simply:

¬P
P
∴ ¬P

The only issue is that people misunderstand what "P → ¬P" means. It doesn't mean what "if ... then ..." means in ordinary English.

Let's suppose an non realist comes to the conclusion that there are no cups. — Sirius

Not all anti-realists claim that.

This is the sort of argument that an anti-realist might make:

P1. A cup exists if and only if there exists some X such that X is a cup
P2. For all X, X is a cup only if X is being seen or used as a cup
C1. Therefore, a cup exists only if there exists some X such that X is being seen or used as a cup

The truth of "a cup exists" (and so the existence of a cup) depends (in part) on an object being seen or used as a cup; its truth conditions are not (entirely) mind-independent.

Note that nothing here entails idealism or phenomenalism; it's perfectly consistent with physicalism and scientific realism.

I would re-write your statement to be: If I am my brain, then "Any position which entails a) I am the person with a body, b) I am not the person in the jar, or c) I am both the person with a body and the person in the jar is wrong."

We then just have to find situations where the antecdent is not satisfied or at least calls it into question. — Hanover

As discussed in the other thread, if the antecedent is false then the material conditional is true, i.e “if P then Q” is true if “P” is false.

And then suppose we could download your brain contents to another brain such that it replicated the mental contents of the first one and gave that other entity the exact feeling of Michaelness you have? Would we have two Michaels? What if the download from Michael 1 to Michael 2 was an actual transfer such that Michael 1 was empty of thoughts once Michael 2 was filled up? Who would be Micheal then? — Hanover

There would be two people who each identify as being Michael, and we would identify one as being the original and the other as being a copy (and they would perhaps identify themselves the same way).

If you were in a vegetative state on a table and your brain was removed to the jar, there'd be no distinction between the you on the table and the you in the jar. That is, there is a position that entails you are the person with the body, you are the person in the jar, and you are the person in the body and the jar. If you say you are not both on the table and in the jar, then which one is you? — Hanover

I’m not sure specifically about a vegetative state, but in the case of brain death there is no person any more, just a body.

In the case I was considering the head is kept alive, like on Futurama. It can think and see and talk.

If I cut off my arm, the arm on the table isn’t me. If I cut out my liver, the liver on the table isn’t me. If I cut off both arms, both legs, and cut out every organ except my brain, heart, and lungs then all the pieces on the table aren’t me. If I cut out my heart and lungs (using a machine to keep oxygenated blood flowing to my brain) then the heart and lungs on the table aren’t me.

I'm just considering a very simple example; Jane and I are decapitated, but our heads (and so brains) are kept alive. Jane's head (and so brain) is attached to my body and my head (and so brain) is placed in a jar.

Given that I cannot be two people it cannot be that I am both the person with a body and the person in the jar. Either I am one of them or neither of them.

My claim is that I am the person in the jar and that Jane is the person with a body. I think that any reasonable person should accept this, showing that the brain plays a special role in establishing identity that is very unlike that of any other organ.

As for the cup in the dishwasher, only someone commitment to sophism would deny that. But non realism isn't reducible to that. A Berkeleyan idealist for eg would say the cup is in the dishwasher since that's how God perceives it, even if no human being does. Both the realist and anti realist have the same answer here. — Sirius

Just as being a king is not a property/condition that is reducible to mere material composition and location in space and time it can be argued that being a cup is not a property/condition that is reducible to mere material composition and location in space and time.

If we abolish the monarchy then it is not the case that those people who were kings no longer exist but it is the case that they are no longer kings, and so no kings exist.

And so one can argue that if we don't see or use anything as a cup then it is not the case that those things which were cups no longer exist but it is the case that they are no longer cups, and so no cups exist.

I don't believe an anti realist goes around saying such and such statement is neither true nor false, anymore than a realist. Every theory of truth is compatible with realism vs anti realism, both classical & non classical logic are likewise compatible with realism & anti realism. In other words, they are of no help here.

Can you cash out non realism in a way that doesn't invoke idealism or phenomenonalism etc ? I don't think so. — Sirius

The term "anti-realism" was coined by Michael Dummett to refer to those positions which reject "semantic realism, i.e. the view that every declarative sentence in one's language is bivalent (determinately true or false) and evidence-transcendent (independent of our means of coming to know which)".

It is certainly the case that phenomenalism (and some idealisms) are anti-realist, but it's not the case that all anti-realisms are phenomenalism (or idealism).

If I woke up with amnesia or hallucinating I was Jesus, with no accurate Hanover memory, I'm still Hanover. — Hanover

I'm not saying that he's not Jane because he doesn't have Jane's memories; I'm saying that he doesn't have Jane's memories because he's not Jane.

Isn't this just a Ship of Theseus question? — Hanover

I think that if we take any one part of the Ship of Theseus and replace it with a new part then it's still the Ship of Theseus, but that if we "replace" my head (and brain) with a new head (and brain) then it's no longer me, it's someone else. I'm the disembodied head living in a jar like in Futurama. There certainly can't be two of me, which would seem to follow from NOS4A2's position.

What is the edited conditional? — TonesInDeepFreeze

Originally I wrote "if I am American then I am the President", but I changed "I" to "Michael" to avoid any debate about indexicals.

That strikes me as ad hoc - introducing a needless distinction in order to maintain a position that has been shown errant.

The topic is the truth of "the cup is in the dishwasher", understood extensionally as being about the cup. We might, separately and distinct from this conversation, talk about the suitability of the use of the word "cup" to talk about the cup before us as distinct from and the cup in the dishwasher. Just as we might talk about the suitability of "King Charles" to refer to Camilla's husband if he had been deposed.

The question at hand is not about the suitability of certain descriptions, but the truth of "the cup is in the dishwasher".

Unless you can show that these are somehow the very same question. — Banno

Take two questions:

1. Is the king in the palace?
2. Is the cup in the dishwasher?

Do we understand (1) extensionally as being about Charles, such that the answer to the question is "yes" if Charles is in the palace, even if the monarchy has been abolished? Or is the answer "there is no king"?

As you say in your profile:

Statements are grammatical combinations of nouns and verbs and such like; Some statements are either true or false, and we can call these propositions. So, "The present king of France is bald" is a statement, but not a proposition.

Anti-realists simply extend this reasoning to a greater class of nouns. Maybe they're wrong to, but at least we're able to address their actual position and not some strawman that treats all anti-realisms as phenomenalism.

However, when you start blaming a society that's bending over backwards to accomodate trans people — Tzeentch

In what way is society "bending over backwards"?

I am not sure what you mean by saying "If I am American then I am the President" is true in propositional logic. — NotAristotle

If "P" is false then "If P then Q" is true.

I am not American, therefore, "I am American" is false, therefore "If I am American then I am the President" is true.

You're not talking about validity there, you're talking about the truth of an "if ... then ..." premise.

In propositional logic "if Michael is American then he is the President" is true, but in "ordinary" language it isn't.

Your real concern is with material implication.

When you take your coffee cup and put it in the dishwasher, does it still exist? — Banno

I think it's important to recognise the distinction between intension and extension.

As an example; if the monarchy in the UK is abolished, does King Charles still exist? Under an intensional reading he doesn't because there are no kings but under an extensional reading he does because the man – Charles – is still alive and kicking (assuming we haven't emulated the French).

This is also where it's important to distinguish between phenomenalism and non-phenomenalist anti-realism (e.g. Kant's transcendental idealism or Putnam's internal realism).

The phenomenalist will argue that under both an intensional and extensional reading "the cup exists (when I don't see it)" is false.

The non-phenomenalist anti-realist will argue that under an intensional reading "the cup exists (when I don't see it)" is false but that under an extensional reading "the cup exists (when I don't see it)" is true.

And of course the realist will argue that under both an intensional and extensional reading "the cup exists (when I don't see it)" is true.

Consider it from your perspective. You undergo the operation. When you wake up do you start identifying as Jane simply because you have her arms and legs and chest and organs? Or do you continue to identify as NOS4A2, having grown up in wherever it is that NOS4A2 grew up in, your (only) parents being NOS4A2's parents? You don't have Jane's memories, not because you forgot, but because you're not Jane.

What if it was just a limb transplant? What if it was just a heart, lungs, kidneys, and liver transplant? How much of the body (excluding the brain) would it take for you to "become" someone else?

But to answer your question, the only "biological marker" that matters to me is the brain because that's where my consciousness is found, either reducible to neurological activity or as some supervenient phenomenon. The rest is incidental.

But suppose a cancerous brain is replaced over-time with a series of machines that work to maintain mental functions until the brain is fully a machine, and no more cancerous brain remains. Are you still your brain? — NOS4A2

In the case of gradual updates, yes, much like the Ship of Theseus. This is the only way I can imagine something like "mind uploads" to actually work (as opposed to the upload being just a copy), as explained on Wikipedia:

"Mind uploading may potentially be accomplished by either of two methods: copy-and-upload or copy-and-delete by gradual replacement of neurons (which can be considered as a gradual destructive uploading), until the original organic brain no longer exists and a computer program emulating the brain takes control of the body."

I would agree that A and B each receive a new lower body, that person A and person B are upper bodies. But this is because the upper body hasn’t died yet, whereas the lower body, being excised from the rest and all vital functions, has. It is only by staving away putrefaction that it is possible to still use it. Bodily survival is the criterion of physical continuity when it comes to personal identity. — NOS4A2

Then what of the head transplant? My head is removed and kept alive (and conscious) by one machine and my torso kept alive by another machine. Are there now two people instead of one? Which one is me? The same procedure is also performed on Jane. Which one is Jane? My head is then attached to Jane's body and Jane's head is then attached to my body. Which organism is Jane and which organism is me? The person with my head and Jane's body will have all of my memories and will think of itself as me, and the person with Jane's head and my body will have all of Jane's memories and will think of itself as Jane. And that's all the matters.

It isn’t the only essential organ. The heart, kidneys, liver, and lungs are also essential. Hence the phrase “vital organs”. And the vital organs are nothing, or at least hindered, without all the rest to protect and support them. — NOS4A2

I was referring to the organ being essential for personhood. The heart and kidneys and lungs and liver are vital to keep the body alive, but we can replace all of them either with artificial machines or the organs of another without dying or becoming a new person.

The same can't be said about the brain. I can't cure myself of brain cancer by removing the entirety of my brain and replacing it with another. That would be to kill me and to give someone else my body.

Someone gave the definition of a person as someone who can sustain themselves: self-sustaining. Given that your person needs to be kept alive by external forces, just like a zygote or fetus, wouldn’t your thought experiment contradict that definition? — NOS4A2

That isn't my definition. Someone in hospital on a ventilator is still a person.

The person uses his lungs and mouth to speak. The brain is only an organ of the person, like the lungs, heart, bones, etc. You are not speaking to a brain any more than you are speaking to a set of lungs. There is more there. — NOS4A2

I'm speaking to a person.

Remove someone's limbs and they're still a person (and the same person). Cut out their tongue and they're still a person (and the same person). Collapse their lungs and they're still a person (and the same person).

But kill the brain and the person is dead, regardless of if the rest of the body is kept alive. The brain is the only essential organ. It either is the person (if reductive physicalism is correct) or it is the organ upon which the person supervenes.

Which is why if this experiment is performed then A and B each receive a new lower body, not a new upper body. And if rather than being cut at the midsection they're cut at the neck, A and B each receive a new torso and limbs, not a new head. That is certainly how they will each consider the matter from their perspective; they won't wake up and believe that they've swapped brains and memories. "I'm A but I remember being B" would be an absurd thing to claim. If that absurdity is required to defend your view on abortion then your view on abortion is absurd.

Or for a real example there's Vladimir Demikhov, who transplanted the upper body of one dog onto another.



There's also Robert White who performed a head transplant on a monkey.

That’s patently untrue. Brains can’t speak. A great deal more is required to utter a single word. — NOS4A2

The brain uses the lungs and mouth to speak. Much like right now you are using a computer/phone to speak to me.

You wouldn’t wake up, for one. You said yourself brain-death is the death of the person, and once the brain is removed from the rest, it’s dead. Second, the vast majority of you is still left on the other table. — NOS4A2

For the sake of this discussion we are able to keep the brain alive after removing it. It's then placed inside another body and all the necessary connections made.

From my perspective I am put to sleep in one body and then wake up in another body. I don't wake up in the same body but with a new brain.

Yes, so this has inconsistent premises:

1. It is raining
2. It is not raining
3. Therefore, is is raining

And this has incoherent premises

1. Red fast what
2. Glooblefooble
3. Therefore it is raining

Let's consider a slightly different example.

A and B are cut in half along the midsection. A’s lower half is attached to B’s upper half and B’s lower half is attached to A’s upper half. They are both kept alive during this operation.

Afterwards, who is A and who is B? Did the person’s identity follow the lower half or the upper half? Does A have a new pair of legs or a new head?

I think it’s obvious: A has a new pair of legs because his identity followed his upper half because that’s where the brain is.

I would say that "this is a valid conclusion" means "this is the conclusion of a valid argument".

Can we say the conclusion is valid or do we reserve the term "valid" only to argument forms and not to conclusions? — Hanover

Premises and conclusions are either true or false.
Arguments are valid if the conclusion follows from the premises.
Arguments are sound if they are valid and the premises are true.

How many brains have you met and had a conversation with? — NOS4A2

Hundreds? Thousands?

I’d say it’s white because that’s what you looked like before.

You think that from my perspective I’d fall asleep looking down at my white-skinned body, the operation would be performed, and then I’d wake up looking down at the same white-skinned body, but with a new brain?

Whereas I think that from my perspective I’d fall asleep looking down at my white-skinned body, the operation would be performed, and then I’d wake up looking down at my new black-skinned body.

I get that, but a 3 permits explosion, which can force anything anywhere. — Hanover

Well, you could have the valid but unsound argument:

1. It is raining
2. It is not raining
3. Therefore, arguments can be both valid and invalid

But regardless of how you get there, the conclusion "arguments can be both valid and invalid" is false.

Why is it still a person if you remove one organ, but not a person if you remove another? — NOS4A2

Because the brain is where personhood is found. Personhood concerns consciousness, and consciousness is what the brain does.

You would still be you and I would still be me. We can compare pictures from before and after to confirm this. We’d be vegetables, but we’d still be occupying the same location in space and time. — NOS4A2

Say currently I'm a white guy and you're a black guy. We have a brain transplant. What colour is my skin after the transplant? I say it's black because my brain has been placed in a black-skinned body, and I am my brain.

As a thought experiment, let's assume that brain transplants are medically possible. My brain is placed in @NOS4A2's body and his brain is placed in my body.

Who is NOS4A2 and who is me after the operation?

The person follows the brain. I have a new body after the operation, not a new brain.

Notice that this is the only organ that this is true for. Switch hearts or lungs or whatever then I have a new heart and lungs. I can never have a new brain. The brain is the seat of personhood.

…or a body. — NOS4A2

Remove the arms and legs and they're still a person. Remove the arms and legs and skeleton (but keep the brain alive) and they're still a person. Remove the arms and legs and skeleton and torso (but keep the brain alive) and they're still a person.

Whereas if you remove the brain but keep the heart and lungs alive then it's not a person.

The only difference between a zygote and a conscious adult is time. — NOS4A2

That is not the only difference. A conscious adult has a functioning brain, a zygote doesn't. That is a very real physical and morally relevant difference.

That's why it's acceptable to end life support on a brain-dead body. There's no relevant purpose in keeping the rest of the organs alive (except to be used in transplants for people who are actually alive).

No 3 is a 4 because no argument can be both valid and invalid.

Yet not a single person you’ve met was a brain. So there is no moral difference. — NOS4A2

I've never met a person who doesn't have a brain.

There is a moral difference between a single-celled zygote and a conscious, talking adult. If you don't agree on this very basic point then I don't know what to tell you.