This article was originally published on The New Philosopher. Written by Russell Blackford.

If our minds are essentially what happens when our brains perform certain kinds of complex computations, then very powerful computers should be able to duplicate them. A time will come soon when sufficiently advanced computer hardware will be able to run a mind just like mine or yours. Perhaps it might even be yours: we seem to be able to imagine transferring someone’s mind from the brain’s wetware to more durable hardware, a hypothetical process called ‘mind uploading’. Would you consider this if it became possible? After all, there might be advantages.

If you uploaded yourself, you might be able to think faster, perceive the world via all sorts of fancy new sensory inputs, and perhaps get yourself a robot body much stronger and more capable than your current one of flesh and blood. Best of all, your new body would be more durable than a human one, and perhaps the new ‘you’ could be transferred from one computer substrate to another, far into the indefinite future. You’d be getting a kind of immortality. Why not grab it with both hands?

One problem is the lingering doubt whether your upload would really be conscious. The computer might be programmed to act and converse just like you, but would the lights be on inside?

There are, of course, many considerations suggesting that our mental states emerge from complex physical structures and events in our bodies, particularly our neural systems. However there’s still some mystery as to how these systems produce mental states. If what really matters is that our brains perform a kind of computation, then mental states could be produced by other physical systems devised and programmed to do the same thing. But what if something else is going on?

For several decades now, American philosopher John Searle has argued that the kind of information processing carried out by digital computers cannot, by itself, cause such things as sensations, beliefs, desires, and thoughts. Searle’s conclusion is that our mental states must be something other than the states of something performing computations. According to this sort of view, thinking is a biological phenomenon like growth, reproduction, and digestion; it is not a computational process, whatever else we might learn about it.

Consider a computer model of a tornado: however accurate and detailed the model might be, it does not possess the real-world twister’s ability to wreak physical havoc. What matters, rather, is the movement of air particles at high speeds, interacting with whatever gets in their path. By contrast, a computer simulation of a tornado does nothing of the kind. Would uploading be like that, creating a detailed model of your brain’s functioning and producing verbal outputs that seem realistically human, but not truly emulating a human mind?

There’s much more to be said here. Most people I encounter seem to divide into two camps: they think Searle is clearly correct, or they think he is making one or another obvious mistake that could be sorted out quickly. I doubt that either position is true; instead, the situation becomes increasingly complex as we dig down into the various ingenious responses to Searle, then into his similarly ingenious replies. I have some tentative views of my own, but for now, let’s move on.

Even if we set aside Searle’s ongoing critique of machine intelligence, another problem awaits if you consider uploading yourself. Would the purported transfer of your mind to a new body be merely the creation of a new person, your digital twin? The apparent advantages of uploading assume that the experiences of the upload are something that you can look forward to, not merely something that happens to another person who is strikingly like you in personality. Perhaps it would be nice if your digital twin enjoyed a lengthy lifespan and other benefits, but that’s only a consolation prize. If you want the jackpot, there must be a plausible sense in which the upload is the original you, or in which you have survived as the upload.

That thought prompts more general questions about the nature of personal identity. In what sense are you still the same person that you were when you were seven years old? In what sense will you still be the same person later in your life? In what sense is it the very same person, when, for example, my friends remember me at seven, or at twenty or forty, or if they imagine me at seventy (if I live that long), or at one hundred (if I live that long)? Is it possible that you and I are, in a sense, not the same people that we were when we were younger, or that we might be in a few decades? Do we exaggerate our continuity, and our mental connection, with past and future selves? If you’re thinking about whether to upload yourself, you’ll need some criterion for whether or not you will still be you, but that appears elusive.

Philosophers like to argue about cases where the very idea of identity is being stretched, perhaps past breaking point. For example, we can conceive of somebody surviving as two separate people if each of her cerebral hemispheres is transferred to a new body, given that there have been surgical patients who’ve survived (or so it appears) with one hemisphere removed. It seems, then, that we should allow for cases of fission of identity. Perhaps we can also imagine science-fictional cases of fusion, where two people merge into one.

The idea of maintaining identity over time is surprisingly difficult when we ask what it really means, and the problems might not become much simpler if we follow the lead of Derek Parfit, who would rather talk about ‘survival’. Perhaps I could survive as two future people, whereas it seems odd (or perhaps even odder!) to say that they are both identical to me without being identical to each other. Still, what counts as survival in a case as extreme as the duplication of my personality and consciousness by a futuristic computer?

Uploading yourself seems to have some pretty impressive attractions, but you’ll want some assurance that they’ll be enjoyed by you. That, however, is exactly where things get difficult. As yet, we have no uncontroversial theory of what (outside of easy day-to-day cases) counts as maintaining the same identity through a process of change, or what should count as survival in a very different physical form. So, what should you do if offered a chance to upload yourself ? Would you go ahead?