From the Robin Catalogue:
A. MS., notebook, G-1903-1.
This lecture is subtitled: “The Categories Defended.” Published: 5.66-81, except 5.71n1 and 5.77n1 (pp. 1-12); 5.88-92 (pp. 48-53). Omitted: whether the three categories must be admitted as irreducible constituents of thought. Objection raised against Schroeder’s and Sigwart’s denial of the Second Category. Discussion of Sigwart’s reduction of the notion of logicality to a quality of feeling (Logical Gef,hl). Objection raised against Kempe’s denial of the irreducibility of the Third Category. Brief comparison of existential graphs with Kempe’s system of graphs. Whether the categories are real, i.e., “have their place among the realities of nature and constitute all there is in nature,” is a question which remains to be answered.