... of the flow of time, and each of the ribbons below represents the stream of consciousness of an individual concerned-the uppermost being that of the thirsty man himself, the others those of his wife, children, or friends. The plus sign early in the drinker's stream of experience stands for the plus value which drinking the water effects-the gratifying taste of the water and the allaying of the discomfort of thirst-real values, whose worth ... — Problems of Conduct • Durant Drake