There is an urban myth that the Stegosaurus had a secondary brain to control its rear legs and tail. Even though it's a myth, such a thing could certainly happen. I want to explore this thought experiment:
At the base of my spine, I grow a secondary brain, a large tail, and an accelerometer like the one in my inner ear. Moreover, sensory data from the tail and the accelerometer is routed only to the secondary brain, not to my primary brain, and my primary brain cannot serve signals to the tail. The secondary brain eavesdrops on nerve signals between my legs and my primary brain, and based on these signals and accelerometer data it positions the tail in ways that improve my balance when I walk and run. The functioning of this secondary brain is very complex and are such as to suffice for consciousenss--say, of tactile and kinesthetic data from the tail and orientation data from the accelerometer--if computational theories of consciousness are correct.
What would happen if this happened? Here is an intuition:
- The thought experiment does not guarantee that I would be aware of data from the tail.
- If a computational theory of consciousness is correct, the thought experiment guarantees that something would be aware of data from the tail.
Thus, the thought experiment gives me a roundabout argument that:
- If a computational theory of consciousness is correct, I am a brain.
So what? Well:
- My hands are a part of me.
- My hands are not a part of any brain
- So, I am not a brain.
- So, computational theories of consciousness are false.
The thought experiment is still interesting even if computational theories of consciousness are false. If we had such secondary brains would we, or anything else, feel what's going on in the tail? I think it metaphysically go either way, depending on non-physical details of the setup.