Our perception of the Past is not marked by the link of succession to as strong a degree as is the perception of the Present and of the instants immediately preceding its point of reality. I usually shave every morning and am accustomed to change the blade in my safety razor after every second shave; now and then I happen to skip a day, have to scrape off the next a tremendous growth of loud bristle, whose obstinate presence my fingers check again and again between strokes, and in such cases I use a blade only once. Now, when I visualize a recent series of shaves, I ignore the element of succession: all I want to know is whether the blade left in my silver plough has done its work once or twice; if it was once, the order of the two bristle-growing days in my mind has no importance — in fact, I tend to hear and feel the second, grittier, morning first, and