The difference between then and now is that we have the Church-Turing Thesis, and the less precise Universal Church-Turing Thesis. A violation of the UCTT woul

The difference between then and now is that we have the Church-Turing Thesis, and the less precise Universal Church-Turing Thesis. A violation of the UCTT would be a Big Deal. Because of this, we now know that previous models of the human brain (as a hydraulic system, as a mechanical system of differential gears, as a weaving machine) are, in fact, also capable of expressing all computable functions (and we can even add Minesweeper and Conway's Game of Life). I don't think anyone is saying that the brain is directly analogous to a computer (in the sense that it has a CPU and volatile memory or anything) so much as the fact that a computer, sufficiently powerful, could compute the same things that our brain is capable of computing, because of Church-Turing.