While taking the bus back from Toronto last night, I found myself wondering again about the brain-in-a-computer issue. While there are legitimate doubts about whether it would ever actually be possible to build a model akin to a human brain inside a machine, it is already the case that people are building successively better (but still very poor) approximations. Eventually, the models may become good enough for the following ethical question to arise.
What I wondered about, in particular, was the ethics of experimenting on such a thing. I have heard people mention, from time to time, the possibility of a ‘grandmother neuron’ charged specifically with recognizing your grandmother. The idea seems very unlikely, given that neurons die with regularity and people rarely completely and exclusively forget how to see their grandmothers. That being said, there is lots of experimental evidence that brain injuries can produce interesting results. As a consequence, the unfortunate, brain-damaged victims of car crashes sometimes find themselves to be the focus of intense interest among cognitive and behavioural psychologists.
If we did have a model brain (say a semi-realistic model fly or beetle brain), we could experiment by disabling sections of it to model the effects. By extension, the same could be done with rat, monkey, or human brains. The question then becomes: is there an ethical difference between experimenting on a mathematical model that behaves like a human brain and experimenting on a real human brain? Does that distinction lie in the degree to which the model is comprehensive and accurate? For instance, a good model brain might respond with terror and confusion if experimented upon.
This is yet another way of getting at the whole ethical question of whether people are simply their material selves, or whether there is something metaphysical to them. I maintain extremely strong doubts about the latter possibility, but still feel that there is an ethical distinction between experimenting on crude or partial brain models and experimenting on complete ones or real brains. I am much less sure about whether there is a meaningful ethical distinction between the last two options.