Previously in series: The Ethics of Simulated Beings, Descartes’s Malicious Demon and The Simulation Argument.

As previously noted in this series, our entire world may be simulated. For all we know we’re sitting on a powerful supercomputer somewhere, the mere playthings of posthuman intelligences.

But this is not the only possibility. There’s another way that this kind of fully immersive ‘reality’ could be realized — one that doesn’t require the simulation of an entire world. Indeed, it’s quite possible that your life is not what it seems — that what you think of as reality is actually an illusion of the senses. You could be experiencing a completely immersive and totally convincing virtual reality right now and you don’t even know it.

How could such a thing be possible? Nanotechnology, of course.

The nano neural net

In his book, The Singularity is Near, futurist Ray Kurzweil describes how a nanotechnology powered neural network could give rise to the ultimate virtual reality experience. By suffusing the brain with specialized nanobots, he speculates that we will someday be able to override reality and replace it with an experience that’s completely fabricated. And all without the use of a single brain jack.

Here’s how:

First, we have to remember that all sensory data we experience is converted into electrical signals that the brain can process. The brain does a very good job of this, and we in turn experience these inputs as subjective awareness (namely through consciousness and feelings of qualia); our perception of reality is therefore nothing more than the brain’s interpretation of incoming sensory information.

Now imagine that you could stop this sensory data at the conversion point and replace it with something else.

That’s where the nano neural net comes in. According to Kurzweil, nanbots would park themselves near every interneuronal connection coming in from our senses (sight, hearing, touch, balance, etc.). They would then work to 1) halt the incoming sensory signals (not difficult — we already know how to use “neuron transistors” that can detect and suppress neuronal firing) and 2) replace these inputs with the signals required to support a believable virtual reality environment (a bit more challenging).

As Kurzweil notes, “The brain does not experience the body directly.” As far as the conscious self is concerned, the sensory data would completely override the feelings generated by the real environment. The brain would experience the synthetic signals just as it would the real ones.