The Commens Dictionary
Quote from ‘One, Two, Three: Fundamental Categories of Thought and of Nature’
There may be a mere relation of reason between the sign and the thing signified; in that case the sign is an icon. Or there may be a direct physical connection; in that case, the sign is an index. Or there may be a relation which consists in the fact that the mind associates the sign with its object; in that case the sign is a name.
‘Index’ (pub. 19.08.13-14:40). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/entry/quote-one-two-three-fundamental-categories-thought-and-nature-5.