I listened to Philip Shepherd’s book Radical Wholeness on Audible while making my giant salad. I was annoyed by his aggressive supernaturalism and the way he attacked rich folks in a tendentious way and then denied that he was attacking them. But he had a good point about the importance of connecting to our bodies.

Because Philip Shepherd was focusing on consciousness and the subconscious, the kind of “connecting to our bodies” he was really talking about was connecting fully to the full, comprehensive representation of one’s body in one’s brain. But crucially, our brain is not just in our head. The large collection of neurons in your gut has been called “The Second Brain.” And humans have other collections of neurons that are larger than the brains of some animals.

Let me illustrate the importance of this fact in a science-fictiony way. The first five links at the bottom of this post demonstrate my interest in Robin Hanson’s book The Age of Em. Suppose you wanted to be frozen when you die with the view that, with some positive probability, your frozen brain would get scanned and you would be able to have a second life as a software human (a brain emulation that Robin Hanson nicknames an “em”). I would strongly advise that you get your whole body frozen, not just your head. I think you will have a better experience as a software human (or at any rate, the software human who thinks they are you will have a better experience) if not only your brain in your head gets scanned and converted to software, but also the brain in your gut and the smaller brains in other parts of your body.

I have no doubt that Philip Shepherd would be aghast at the idea of becoming a software human without a literal body. But the body that counts for one’s experience is the full, comprehensive brain representation of your body including your entire nervous system, plus as full a representation as possible of the rest of the body systems to the level of detail that your brain experiences them. (Particularly important here is the hormonal system, which has a big effect on brain parameters.) As inputs to the brain emulation proper, you need not only the world-facing senses, but also all dimensions of interoception: all aspects of body state as communicated to the brain. And to get interoception right, you need to have a reasonable model of the body systems outside the extended brain.

Update: Robin Hanson gives these comments on Twitter:

I agree that ems will want to include models of the parts of our "brain" outside our heads. However, it is less obvious to me that we can't usefully substitute a generic version of that for any one person, if only their head was frozen.

That is, I'm pretty sure we need your particular head to make a model of you, but less sure we need your particular body to make a creature who remembers being you and enjoys their body.

I respond:

There is some risk aversion in what I wrote. As you say, it might be OK to just have the head, but it might not be.

Robin replies:

Sure, but people are pretty price sensitive here, and head only can be a lot cheaper.

Related Posts:

• On Being a Copy of Someone's Mind

• Will Your Uploaded Mind Still Be You? —Michael Graziano

• The Virtual Reality Theory of Dualism

• Interstellar Travel and Uploaded Humans

• Consensual, Non-Solipsistic Experience Machines

• On the Effability of the Ineffable

• Frank Wilczek: Are We Living in a Simulated World?

• The Argument that We Are Likely to Be Living Inside of a Computer Simulation

• Cyborgian Immortality

• Christof Koch: Will Machines Ever Become Conscious?

• The Mystery of Consciousness