The thing that you have to understand is that just because we, as humans, can't see predictable patterns in a set of data doesn't mean that they aren't there. Neural networks are REALLY good at finding patterns that humans cannot see. The first time I ever implemented a neural network was to recognize hand-written digits. It was able to correctly classify some hand written digits that were written so poorly that I, a human, could not tell for sure if they were one digit or another.

Human behavior is not totally unpredictable. Especially given large numbers of humans. This is besides the point though. The actual cause of price fluctuations is completely irrelevant actually. My computational model has no idea what is causing prices to change because it doesn't matter at all. All that matters is that there are repetitive patterns in the data (which there are). The neural network learns these patterns, and is able to use them to accurately predict bitcoin prices.

You can say you don't believe that bitcoin prices can be mathematically modeled, but it is still true - it's exactly what I'm doing (relatively successfully) here.