after Mackie, I'm going to say asking anyone to defend their values is a joke.

I provided fairly extensive argument earlier in the thread.

Thats only a problem if you believe value derives from evolution, a proposition you presented but which I dont hold. — Ourora Aureis

If not evolution then from God?

You even mentioned social and cultural factors yourself, but then you immediately overule them with the gene propagation idea. — Ourora Aureis

I wrote that valuing human life is ingrained and the reason (you requested reasoning) I think it's ingrained is because it promotes gene propagation and the survival of our species.

I already presented why I think people hold these values, and its mostly a case of religious philosophy, not some innate emotional reaction that derives from their biology. — Ourora Aureis

I thought you were asking me why I value zygotes. Granted religious thought has been somewhat ingrained in me even though I've never really been religious.

There is a moral difference between a living body with a functioning brain and a living body without a functioning brain.

Brain death is death of the person.

And if the brain could be removed but kept alive then even though it's a single organ it's also a person.

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

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.

The one on the left is what the one on the right looked like about 9 months earlier. In those 9 months, what changed for you? — NOS4A2

Continuum fallacy.

…or a body.

The only difference between a zygote and a conscious adult is time. All adults were zygotes. The so-called moral difference is immeasurable.

I never said there is no difference, only that one has developed out of the other.

There are any number of differences between them. The differences/similarities are what is relevant to the debate. You can decide they are sufficiently similar to warrant assessing them as the same kind of thing, and I can judge them sufficiently different to assess them as a different kind of thing. The judgements are subjective; there is no objectively correct answer.

The differences between you now and you at the beginning of your life are profound, but at each stage you were present and identical to both. No kind of thing died and was replaced by another kind of thing.

…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).

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.

The differences between you now and you at the beginning of your life are profound, but at each stage you were present and identical to both. — NOS4A2

That depends entirely on how you account for an individual identity. There is no objective basis for doing so.

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

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?

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.

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.

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

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

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.

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

That depends entirely on how you account for an individual identity. There is no objective basis for doing so.

Sure there is. Technically we could film or track the entire life of a human being from beginning of his lifecycle to the end, and the identity of that being remains the same.

Sure there is. Technically we could film or track the entire life of a human being from beginning of his lifecycle to the end, and the identity of that being remains the same. — NOS4A2

You're claiming that this temporal-causal relationship between the stages identify an individual identity. That's a consistent definition, but not objective.

I am a human being: a self-sustaining complex organism, with a functioning brain, capable of thoughts, dreams, and emotions. A zygote is not a human being, per this definition. Rather, it is an entity that has the potential to develop into one or more human beings. Therefore I do not share an identity with the zygote from which I emerged. You will disagree, because of the definition you've chosen. My point is that the definition you choose is subjective.

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.

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.

Hundreds? Thousands?

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

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.

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.

All human being go through that stage, just as many of them go through the stage of childhood. Zygotes, neonates, children, adults—these are stages, not different organisms.

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.

This scenario isn't that far fetched actually as this video analysis shows. It's only a few minutes and worth a watch, particularly at around 1:40.

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.

Mine was funny. Yours is disturbing.

If you awoke with your brain in a different body, and you were a hot girl, I'd be all over that.

Now we're even with the disturbing posts.

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

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.

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.

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?

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.

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.

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.

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?

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.