Effort supposes resistance. - Charles Sanders Peirce

We think only in signs.

Now, let there be an indefinite succession of these inferential acts of comparative perception; and it is plain that the last moment will contain objectively the whole series. Let there be, not merely an indefinite succession, but a continuous flow of inference through a finite time; and the result will be a mediate objective consciousness of the whole time in the last moment. In this last moment, the whole series will be recognized, or known as known before.

Signs are of three classes, namely, Icons (or images), Indices, and Symbols. Article 6. An icon is a sign which stands for its object because as a thing perceived it excites an idea naturally allied to the idea that object would excite.