The Commens Dictionary
Quote from ‘The List of Categories: A Second Essay’
Had there been any process intervening between the causal act and the effect, this would have been a medial, or third, element. Thirdness, in the sense of the category, is the same as mediation.
‘Thirdness’ (pub. 09.03.13-12:46). 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-list-categories-second-essay-0.