The Commens Dictionary
Quote from ‘A Syllabus of Certain Topics of Logic’
A heavily marked line without any sort of interruption (though its extremity may coincide with a point otherwise marked) shall, under the name of a line of identity, be a graph, subject to all the conventions relating to graphs, and asserting precisely the identity of the individuals denoted by its extremities.
Peirce, 1903, p. 18; CP 4.406
‘Line of Identity’ (pub. 18.03.18-15:32). 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-syllabus-certain-topics-logic-25.