Silicon Immortality: Downloading Consciousness into Computers

While medicine will advance in the next half century, we are not on a crash-course for achieving immortality by curing all disease.  Bodies simply wear down with use.  We are on a crash-course, however, with technologies that let us store unthinkable amounts of data and run gargantuan simulations.  Therefore, well before we understand how brains work, we will find ourselves able to digitally copy the brain's structure and able to download the conscious mind into a computer.

Silicon Immortality

If the computational hypothesis of brain function is correct, it suggests that an exact replica of your brain will hold your memories, will act and think and feel the way you do, and will experience your consciousness — irrespective of whether it's built out of biological cells, Tinkertoys, or zeros and ones.  The important part about brains, the theory goes, is not the structure, it is about the algorithms that ride on top of the structure.  So if the scaffolding that supports the algorithms is replicated — even in a different medium — then the resultant mind should be identical.  If this proves correct, it is almost certain we will soon have technologies that allow us to copy and download our brains and live forever in silica.  We will not have to die anymore.  We will instead live in virtual worlds like the Matrix.  I assume there will be markets for purchasing different kinds of afterlives, and sharing them with different people — this is future of social networking.  And once you are downloaded, you may even be able to watch the death of your outside, real-world body, in the manner that we would view an interesting movie.

Of course, this hypothesized future embeds many assumptions, the speciousness of any one of which could spill the house of cards.  The main problem is that we don't know exactly which variables are critical to capture in our hypothetical brain scan.  Presumably the important data will include the detailed connectivity of the hundreds of billions of neurons. But knowing the point-to-point circuit diagram of the brain may not be sufficient to specify its function.  The exact three-dimensional arrangement of the neurons and glia is likely to matter as well (for example, because of three-dimensional diffusion of extracellular signals).  We may further need to probe and record the strength of each of the trillions of synaptic connections.  In a still more challenging scenario, the states of individual proteins (phosphorylation states, exact spatial distribution, articulation with neighboring proteins, and so on) will need to be scanned and stored.  It should also be noted that a simulation of the central nervous system by itself may not be sufficient for a good simulation of experience: other aspects of the body may require inclusion, such as the endocrine system, which sends and receives signals from the brain.  These considerations potentially lead to billions of trillions of variables that need to be stored and emulated.

The other major technical hurdle is that the simulated brain must be able to modify itself. We need not only the pieces and parts, we also the physics of their ongoing interactions — for example, the activity of transcription factors that travel to the nucleus and cause gene expression, the dynamic changes in location and strength of the synapses, and so on. Unless your simulated experiences change the structure of your simulated brain, you will be unable to form new memories and will have no sense of the passage of time.  Under those circumstances, is there any point in immortality?


SiliconImmort3The good news is that computing power is blossoming sufficiently quickly that we are likely to make it within a half century.  And note that a simulation does not need to be run in real time in order for the simulated brain to believe it is operating in real time.  There's no doubt that whole brain emulation is an exceptionally challenging problem.  As of this moment, we have no neuroscience technologies geared toward ultra-high-resolution scanning of the sort required — and even if we did, it would take several of the world's most powerful computers to represent a few cubic millimeters of brain tissue in real time.  It's a large problem.  But assuming we haven't missed anything important in our theoretical frameworks, then we have the problem cornered and I expect to see the downloading of consciousness come to fruition in my lifetime.

(I originally published this essay in John Brockman's This Will Change Everything, a collection of answers to the Edge.org annual question)

Leave a comment

From the Blog

  • The Brain and the Law
    The Brain and the Law

    Interested in the intersection of the brain and the legal system? Watch a talk I delivered at the Royal Society for the Arts in London, entitled "The Brain and the Law".

  • A note about head shape in mummies
    A note about head shape in mummies

    A few months ago I scanned a 3,000 mummy. What can (and can't) be concluded based on his perspicuously elongated skull shape, known as dolicocephy (elongated head)?  

  • Schwarzenegger on Incognito
    Schwarzenegger on Incognito

    What a wonderful shot of caffeine it was to find my childhood hero lauding my book in the New York Times.

  • Why public dissemination of science matters
    Why public dissemination of science matters

    Communicating science to the public can take time away from a busy research career. So why should scientists do it? I offer a manifesto of six reasons in the Journal of Neuroscience. 

Newsflashes

Book of the Week

Sum was selected as Book of the Week by both The Guardian newspaper and The Week newsmagazine.

NY Times Oped

Read David's Op-Ed piece in The New York Times regarding time and Obama's withdrawal plan.

Emily Blunt reads for the Sum audio book

Hear the actress Emily Blunt (Young Victoria, Devil Wears Prada) read "The Cast" from Sum. She is one of the dozens of terrific actors who read for the audio book.

You are here:   HomeBlogSilicon Immortality: Downloading Consciousness into Computers


Coming in 2014