In the visual realm, a concretum is a color-spot moment, which may be construed as the sum of a color, a visual-field place and a time, all of which stand in a peculiar relation of togetherness. Goodman adopts this relation as a primitive and then shows how, by means of it, it is possible to define the concept of the concrete individual as well as the various relations of qualification in which qualia and certain sums of qualia stand to the fully or partially concrete individuals that exhibit them.