Altered Carbon is a 2003 science fiction novel written by Richard K. Morgan, which has recently been made into a gritty, futuristic, and definitely R-18 TV series. The central plot device revolves around pieces of technology called ‘cortical stacks’. They are small, palm-sized devices that are implanted at the top of the spinal column and function as digital receptacles for the human consciousness. When you die, as long as your ‘stack’ isn’t damaged, you can be brought back to life by having your consciousness downloaded from your cortical stack into the cortical stack of another body (called a ‘sleeve’), which can be either a real human body or a synthetic, grown one. This transferral process is called ‘needlecasting’ and usually involves deleting the consciousness in the first stack before making the transfer. In this way, the super-rich (called ‘meths’, a reference to the long-lived Methuselah of Biblical fame) have allegedly achieved immortality. In this article, I want to investigate this assumption by asking, are you the same person after needlecasting as you were before?
Think back to when you were ten years old. Was that child you? Bear in mind that not only is virtually nothing physical about you the same now as it was then, you almost certainly have completely different preferences, beliefs, attitudes, goals, thoughts… even your personality will have changed. If that child was you, the same person you are now, what is it that accounts for this continuity in identity?
17th century English philosopher John Locke addresses this problem in his An Essay Concerning Human Understanding. He starts with an atom and declares that it is the “same with itself” at any instant of its existence. Although we now know that atoms aren’t fundamental particles, Locke would certainly have been referring to an irreducible, unchanging, fundamental particle of nature. Nowadays, we would reserve this title for quarks and electrons. Perhaps it would be better if we paraphrase Locke and say that a fundamental particle is the “same with itself” at any instant of its existence. Identity, at the level of fundamental particles, coincides with physical existence. The fact of existence ensures continuity of identity.