The Commens Dictionary

Quote from ‘L [R]’


These three great divisions, Idioscopy, Cenoscopy, and Mathematics, together constitute the aggregate of those sciences which are sometimes called Theoretical Sciences, but which I prefer to call the Heuretic Sciences, or the Sciences of Discovery, because, on the one hand, I am unable to attach any definite meaning to the word “theoretical” that is in truth applicable to these forms of activity and to no others, while, on the other hand, I do find that the more intimate my acquaintance with them becomes, the more emphatically they show themselves as severed from all other human doings by the almost absolute singlemindedness, proportionally to the success of the exertions, with which they are animated by one motive, the desire to learn what is not already known, this learning being the object of desire on its own account only.

1906 [c.]
MS [R] 601:24-25
‘Heuretic Science’ (pub. 19.05.15-16:12). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from
May 19, 2015, 16:12 by Mats Bergman