Everywhere science is enriched by unscientific methods and unscientific results,... the separation of science and non-science is not only artificial but also detrimental to the advancement of knowledge. If we want to understand nature, if we want to master our physical surroundings, then we must use all ideas, all methods, and not just a small selection of them.

Against method: outline of an anarchistic theory of knowledge (ed. Not Avail, 1975)