Of the making of windows there is no end. —Anonymous, Window-making (1910)

The learning of every word in a language, of every fact, argues organised reaction, and every word or fact so acquired implies an established trend. From week to week, perhaps from hour to hour, we are building up and breaking down temporary habits. [...] The way I turn over the pages of a book is a distinct trend, the manner in which I open and shut the door, the fashion in which I read, and the like. [...] As we reflect we become convinced that a vast number of actions are repeated, that the majority of our activities resemble each other, that the various new tasks we perform are new but to an insignificant degree, and that certain principles elaborated lie at the foundation of activity as a whole.