We read contrast, our cognition depends on it; therefore we think it is important. And yet the fundamental contrast of dark and light, positive and negative, can hardly be an artifact of cognition. The nearest thing I know to a general explanation of its appearance in the world is the one given by Spencer Brown. His beautiful account of all mathematics arising from the contrast (distinction) between nothing and something tries to show how all structure and form, at the most elementary level, come from contrast. But why the systems in which living structure appears seem to have contrast more strongly than others — that remains a mistery.
— Alexander, Christopher. The Nature of Order, an Essay on the Art of Building and the Nature of the Universe. Book One: The Phenomenon of Life. 1980. Berkeley, California: The Center for Environmental Structure, 2002.
