The Commens Dictionary
Quote from ‘C.S.P.'s Lowell Lectures of 1903 2nd Draught of 3rd Lecture’
An ens rationis is something whose being consists in the possibility of something being true about something else.
MS [R] 462:34-36
‘Ens Rationis’ (pub. 25.11.14-17:15). 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-csps-lowell-lectures-1903-2nd-draught-3rd-lecture.