The Brain Upload

The scenario

The technology is imagined but the logic is precise. Your brain is scanned at a resolution fine enough to capture the state of every neuron and synapse. This information is uploaded to a computer, which runs a simulation of your brain's processes. The resulting digital entity has your memories, your patterns of thought, your personality quirks, your self-model. It reports that it is you, and it believes this.

Your biological brain, meanwhile, is destroyed. There is now a digital entity that appears to be you, and a dead body. Did you survive?

Two theories, two answers

The psychological continuity answer says yes. What matters for survival is that your memories, personality, and cognitive patterns persist in a causally connected way. The digital entity has all of these, connected through the scanning process to your biological original. You are a pattern of information, and patterns can be implemented in different substrates.

The biological continuity answer says no. You were a particular biological organism, and that organism died. The digital entity is a very good copy, perhaps better than any copy made before, but a copy is not the original. The scanning process created a new entity and ended an existing one. From the outside, the result looks like survival. From the inside, there may have been nothing but death.

The harder question

Even if you accept psychological continuity and say the upload survives, a further problem remains. Survival, intuitively, requires continuity of experience: that there is no gap, that the stream of consciousness continues unbroken from biological to digital. Sleeping may involve such a gap; we tend to accept it. But is the gap during scanning and upload relevantly different?

Derek Parfit's view was that survival in the strict sense, the persistence of a numerically identical person, matters less than we think. What actually matters is psychological continuity and connectedness, which comes in degrees and can branch. If a perfect upload exists, most of what you care about in your own survival is preserved, even if the question of strict identity has no determinate answer.

The upload case also raises a question that the older identity debates did not: if the digital entity is genuinely continuous with you, is it a person in the full moral sense? Does it have rights? Can it suffer? Does it die if the server is shut down? These are no longer purely philosophical questions.