Affective communications accompany all human interactions, including psychotherapeutic practice, but their meaning remains debated, both within psychoanalysis and in philosophy and neuroscience. In this chapter, the author sorts out some of the conflicting claims made by scholars in these disciplines, each of which brings its own terminology, methods, and findings to the complexities of human emotion. He provides these by arguing for an intersubjective approach to affect in clinical practice against the prevalent naturalizing or biologic reductionism. The author focuses on the work of Rene Descartes, who famously theorized a mind–body dualism based on religious suppositions. Descarte’s religious conception of an insubstantial soul linked mysteriously to the physical body has faded, but the almost unavoidable tendency to think either in terms of biophysical causation or of personalistic wishes and desires persists. Some social theorists strongly contest the over-generalization of neuroscience research findings about the core emotions and their universal facial expressions to other disciplines.