The formation of introspective concepts follows the same principles as the
formation of extrospective concepts. A concept pertaining to consciousness is a
mental integration of two or more instances of a psychological process
possessing the same distinguishing characteristics, with the particular
contents and the measurements of the action’s intensity omitted—on the
principle that these omitted measurements must exist in some quantity, but
may exist in any quantity (i.e., a given psychological process must possess
some content and some degree of intensity, but may possess any content or
degree of the appropriate category).
No concept man forms is valid unless he integrates it without contradiction
into the total sum of his knowledge.