The Commens Dictionary
Quote from ‘Grand Logic: Book I. Of Reasoning in General. Introduction. The Association of Ideas’
As experience clusters certain ideas into sets, so does the mind too, by its occult nature, cluster certain ideas into sets. These sets have various forms of connection. The simplest are sets of things all on one footing and agreeing in each belonging to the set. Such a set is a class. The clustering of ideas into classes is the simplest form which the association of ideas by the occult nature of ideas, or of the mind, can take.
‘Class’ (pub. 26.07.15-15:49). 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-grand-logic-book-i-reasoning-general-introduction-association-ideas-1.