The context in which I came to think about the issue was again a discussion of futurist hopes (although it had not started out as that), specifically "brain uploading" or "mind uploading". The hope that something like that would be possible sometime in the future is based on the following claims:
- We are our minds.
- Our mind is best understood as information stored and/or a computer program running on the "wetware" of the brain.
- A simulation of a mind is a mind. Just as a simulation of a Windows environment on a Linux machine allows Windows programs to run, a simulation of a brain in a computer would allow our mind program to run on that computer.
- Consequently, if we could scan that program and the information (memories) off the brain and simulate it in a computer, we would be in that computer, and thus could achieve immortality (until humanity cannot afford to keep cyberspace running any more, that is, which might be as soon as in a few decades anyway when fossil fuels run out).
In the present case the specific mistake is to think of the mind as a thing that can be moved, or perhaps at least copied, from the body into a computer, which is essentially a form of Cartesian mind-body dualism. To get over this mistake, and to raise one's consciousness about the ease with which we make it, one could consider historical instances of the same error.
It was once seriously believed by many people that life was something like a substance that had to be present in a matter to, well, make it alive, the famous elan vital. We now know that there is no such substance. Life is not a thing, it is instead a biochemical process of metabolism, homeostasis and growth. The process can be stopped by killing an organism but it cannot be taken out of it and transferred into the corpse of a different organism or into a stone, for example. It cannot be stored, touched, weighted, seen or whatever because it is not a thing, just like "falling" or "writing" is not a thing.
Similarly, the mind is the process of the brain operating. To believe in mind uploading is to visualize the mind as a thing that can moved or copied from here to there.
However, the believer in mind uploading might counter that some processes can, in a way, be copied or moved from one substrate to the other. There was once a belief that fire was an element comparable to air, water and earth. Setting aside the fact that the four classical elements have been superseded anyway, it is very clear today that fire simply does not fit into that list. The other three are substances but fire is not; it is a process, the rapid oxidation of a substance. So with that in mind, the believer in mind uploading might say: aha, but fire can be copied and moved from one substance to another, so why not a mind? The same goes for certain other processes, such as movement in a direction; a momentum can also be transferred from one object to another.
The question is then, if you take a burning match and transfer the flame to a puddle of oil, is the burning of the match the same "thing" (for want of a better word) as the burning of the oil? Well no, the chemistries involved are very different. Is a momentum transferred from one ball onto another the same thing? Again, no, angles, speeds, etc may be very different. Most importantly, however, the match is not the oil, and the second ball is not the first ball.
As mentioned above, it is not only some of the claims that are wrong, it is all of them. So let us rephrase them to make them less wrong:
- We are our bodies.
- Our mind is best understood as our bodies thinking.
- A simulation of a mind is not a mind but merely a simulation of a mind because there is no actual body involved.
- Even if all you care about is the thinking, and argue that the thinking could also be done by a computer, it would still not be you doing the thinking but the computer. Thus you will not achieve immortality through mind uploading, at best some of your thoughts would.
A believer in mind uploading would perhaps walk out of the room, get old and die thinking, "now I am immortal because another me is in the computer". But one might reasonably wonder why the same person could not simply have children, write a book or do some great good in the world, and then grow old and die thinking, "now I am immortal because I will live on in what I leave behind". Same thing really.
But sorry about the digression. The purpose of this post was to point out that we have the bad habit of reifying processes (and abstract concepts, but that is another matter), and that this habit leads us to have unrealistic ideas about what happens and what could possibly happen. Your mind cannot be copied or moved. Your mind is your body thinking; if something else is thinking the same thoughts - be it a computer or your identical twin - it is not your mind any more.