Asked by: Cian McCarthy, Cork, Ireland


Our sense of self emerges from the activity of a poorly understood network of neurons, glial cells and blood vessels in the brain, which together produce the electrical and chemical processes that give us our thoughts and consciousness.

One day, it might be possible to scan all of this activity with perfect fidelity – this would be a hugely intensive process, involving recording the activity of every cell and chemical at an atomic level. This digital scan could be turned into a computer simulation, essentially allowing you to go on living after death. In theory, the simulated version of your brain would believe that its sense of self had been successfully uploaded, transferred from a biological body to an artificial one.

However, it’s not quite as simple as that. If scientists can develop a way to perfectly scan the brain without destroying it (which isn’t a given), then your original brain (and sense of self) would still exist, trapped in a body that will eventually fail. Your digital self might come to the realisation that it’s a copy, triggering an existential crisis.

And what if someone decides to make a hundred copies of this digital self? Now there are a hundred digital versions of ‘you’, each with its own sense of self. Is each of these selves equally valid? Does the second sense of self know that it’s the original copy, and thus expect a higher status? Could the separate selves decide to share their experiences and become a super-intelligent ‘hive mind’?

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We don’t yet know the answers, but one way to limit any potential complications might be to become immortal piece by piece. We naturally change as we age, so if you slowly replaced failing biological tissue with computerised prostheses, then by the time all of your body and brain had been replaced, your sense of self will have been transferred without leaving behind a biological remnant.

Just watch out for the delete key… a digital brain is much easier to wipe than an organic one!

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Dr Peter Bentley is a computer scientist and author who is based at University College London. He is the author of books including 10 Short Lessons in Artificial Intelligence and Robotics and Digital Biology: How nature is transforming our technology and our lives.