Emmet, Dorothy, ed.  "The Pardshaw Dialogues: Sense Awareness and the Passage of Nature."  Process Studies 16, no. 2 (Summer 1987): 83-145.

Abstract

Contemporary research interest in Whitehead's philosophy of science of the middle period is based mainly on The Concept of Nature.  Participants included R. B. Braithwaite, who was involved in discussions in the 1920s; Margaret Masterman, who finds relevance for model of flow of language with emphasis points; Rupert Sheldrake, who was invited to elucidate formative causation; Johnathan Westphal, who appreciates secondary qualities in nature; Christopher Clarke, who derives space-time through events; Dorothy Emmet, who sees causation from awareness of on-going process prior to abstraction.  The dialogues give a richer view of sense-perception than the sense-data view.  [Abstract from The Philosopher's Index]