Signs involve heterogeneity in at least three ways: first, in the object which bears or emits them, and is necessarily on a different level, as though there were two orders of size or disparate realities between which the sign flashes; secondly, in themselves, since a sign envelops another 'object' within the limits of the object which bears it, and incarnates a Repetition and Difference natural or spiritual power (an Idea); finally, in the response they elicit, since the movement of the response does not 'resemble' that of the sign.