Russell’s study of the biologist and psychologist Richard Semon is traced to contact with the experimental psychologist Adolf Wohlgemuth and dated to the summer of 1919. This allows a new interpretation of when Russell embraced neutral monism and presents a case-study in Russell’s use of scientific results for philosophical purposes. Semon’s distinctive notion of mnemic causation was used by Russell to clarify both how images referred to things and how the existence of images could be reconciled with a neutral monist metaphysics.
"Richard Semon and Russell’s Analysis of Mind,"
Russell: the Journal of Bertrand Russell Studies:
2, Article 3.
Available at: http://digitalcommons.mcmaster.ca/russelljournal/vol26/iss2/3