I didn't mean to say that it is the only problem. It is more like the "meta problem" as far as theory is concerned. There are many parameters (layers, nodes, c

I didn't mean to say that it is the only problem. It is more like the "meta problem" as far as theory is concerned. There are many parameters (layers, nodes, connectivity, drop off, number of trials etc). Right now they are guessed at by trial and error. The thing preventing you from saying, "Oh, just reduce the layers by 1, and add more nodes" is the non-linearity.