Professor Hering's philosophy of the unconscious is of extreme simplicity. He rests upon a fact of daily and hourly experience, namely, that practice makes things easy that were once difficult, and often results in their being done without any consciousness of effort. But if the repetition of an act tends ultimately, under certain circumstances, to its being done unconsciously, so also is the fact of an intricate and difficult action being done unconsciously an argument that it must have been done repeatedly already.