I don't think the non-linearity argument is too convincing. Certainly, I accept that you cannot simulate a specific brain/mind - that is, if you somehow knew th

I don't think the non-linearity argument is too convincing. Certainly, I accept that you cannot simulate a specific brain/mind - that is, if you somehow knew the exact structure and inner workings of a specific mind that you could then run a simulation of that mind which returns the same outputs as the original mind. I can buy that our simulations of non-linear problems will not fully match 'reality' and cause divergence. However, that doesn't mean we cannot run a model. Exactly what the model's output 'means'... well, that's a different question. To use his examples, our simulations of weather or the stock market do not produce the same output as the future. But their outputs (hopefully) represent actually realizable states of the world. In other words, as long as our model gives us 'human enough' output, then I guess it's sufficient? I mean, it really comes down to 'why do you want to simulate the human brain'. If you want to be able to upload your brain, then that probably isn't good enough. But I can imagine for various other uses, it could be enough. I do think Kurzweil is at best... wildly optimistic though.