The Commens Dictionary
Quote from ‘A Guess at the Riddle’
The First is that whose being is simply in itself, not referring to anything nor lying behind anything. The Second is that which is what it is by force of something to which it is second. The Third is that which is what it is owing to things between which it mediates and which it brings into relation to each other.
EP 1:248; CP 1.356
‘Secondness’ (pub. 09.03.13-12:43). 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-guess-riddle-8.