The Commens Dictionary
Quote from ‘Miscellaneous Fragments [R]’
“Instinct” is nothing but the generalization of a certain kind of single voluntary responses of single animals to single stimuli, namely of those responses that have tendencies to produce similar ultimate (and usually beneficial) effects on the welfare of those animals or of their progeny, which effects, however, they can hardly be supposed to have divined and certainly not to have ascertained by reasoning.
MS [R] 1573
‘Instinct’ (pub. 08.10.18-11:12). 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-miscellaneous-fragments-r-12.