From the Robin Catalogue:
A. MS., G-1898-1, pp. 1-23, incomplete, with 3 loose sheets (notes for lecture).
Selection published: 4.1-5. Deleted: pp. 1-4, 11-17, 18-22 on the relationship between philosophy and mathematics and between philosophy and the exact sciences, on the gross abuse of the word “realism,” on the Peircean categories and the logic of relatives. CSP offers an explanation (suggested by a theorem of the logic of relatives that no polyads higher than triads are required to express all relations) of why his list of categories is complete. Co-discoverer, with De Morgan, of the logic of relatives, CSP introduces the reader to that logic by means of existential graphs.