This essay illustrates the main aspects of the discussion between Brentano and Stumpf about «tonal fusion» (Tonverschmelzung). In his Tonpsychologie, Stumpf essentially moved from a Brentanian standpoint. Yet, he did not adopt Brentano’s subsequently developed new theory of «sensible qualities», so that a polemic eventually arouse between them. Far from representing a marginal issue, the episode is relevant to our understanding of their relationship. The discussion as to the mechanism of tonal fusion reveals a general divergence between Brentano and Stumpf concerning the idea of human sensibility as a whole and of the method of psychology.
