>By 'entire field' you mean handwriting recognition? Classification of high-dimensional data is a huge portion of machine learning. >They reduce the search sp

>By 'entire field' you mean handwriting recognition? Classification of high-dimensional data is a huge portion of machine learning. >They reduce the search space by limiting themselves to combinations of typical pen movements. "They reduce the search space by limiting themselves to gradients of nearby pixels. Very smart, but I don't see how convolutional neural networks can be applied to machine learning in general." All of machine learning involves some prior knowledge -- the question is always how much and at what level of abstraction.