This subseries contains seven notebooks and a file of compiled notes that were originally dispersed throughout the collection. Written by RWS, these notes express his thoughts in varying depths on topics such as biographical remarks, personal notes, and philosophical musings. The loose handwritten notes contain fragments of ideas and notes in outline form, while the notebooks highlight a broader range of ideas. The first notebook examines relative motion, realism, and secular humanism. The second notebook mainly deals with causality, determinism, notes from "Soviet Studies in Philosophy," and religion. The third contains thoughts on relativity, American global policy, economics, and Marx. The fourth examines the thoughts of other philosophers' (including, Toynbee, Sartre, Bernstein, and Robespierre) and RWS's own thoughts on democracy. The fifth notebook begins with Greek philosophy, and later remarks on human consciousness, referential thinking and problems, and perceptual experience. The sixth notebook includes RWS's musings on topics of matter, materialism, American perception, causality, determinism, dialectical materialism, and Marxism. Also included in this notebook are references to his article, "In What Sense Is Valuation Objective in Import?" The seventh notebook addresses RWS's ideas about agential level of causality, double-knowledge, relative motion and Einstein.