The Commens Dictionary
Quote from ‘Letters to Lady Welby’
The qualisign […] has no identity. It is the mere quality of an appearance & is not exactly the same throughout a second. Instead of identity, it has great similarity, & cannot differ much without being called quite another qualisign.
‘Qualisign’ (pub. 09.08.13-13:46). 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-letters-lady-welby-29.