We can say, at once, that a sign must have these three characters: First, it must be a recognizable object in itself. Secondly, it must be determined to correspond, according to some principle, and by some species of causation, with something else, called its Object. In a word, whether physically, rationally, or otherwise, directly or indirectly, its Object, as agent, acts upon the sign, as patient. [—] But thirdly, the Sign, in its turn, acts upon the Interpreter-mind, or the quasi-mind corresponding thereto, and produces the Interpretant; and this action is essentially relative to the Object.