Freud and the Legacy of Sensory Physiology

In the literature on the philosophical background of psychoanalysis, Freud is often placed in a Kantian tradition via his engagement with authors such as Schopenhauer, Herbart, Lipps, Meynert, and, especially, the physiologists Hermann von Helmholtz, Emil du Bois-Reymond, and Freud’s mentor during his medical studies, Ernst Theodor Brücke. This chapter explores how Freud imported – and extended – Helmholtz’s theory of perception in developing his new psychology. Further, it is argued that the physiologists’ work on perception paved the way to an epistemology that would today be described as a type of epistemic structural realism, which, due to their influence, was also adopted (and again extended) by Freud. Following this assessment, the chapter examines how the theories of perception proposed by Helmholtz and Freud are currently being recast in similar formats under so-called predictive processing and embodied inference approaches in the neurosciences and philosophy of mind, as well as evaluating its epistemological implications. The chapter concludes by schematically describing how the legacy of sensory physiology remained present (via Freud) in the work of the Kleinian school of psychoanalysis, and how this presents an isomorphism with predicted processing accounts of fantasy, dreaming, and primal forms of mental activity.