Ian Hacking on suggestibility: from psychology to logic

This paper aims to clarify Ian Hacking’s understanding of a key psychological concept: suggestibility. This is the phenomenon whereby a person adopts an external idea as if it originated from within themselves. The central text of reference is Hacking’s Rewriting the Soul, in which he examines the emergence of multiple personality disorder. Throughout his account, Hacking repeatedly expresses a critical stance toward the term and explanations based on suggestibility. He characterizes it as a vague notion and a superficial explanation of multiple personality (pp. 255–256). However, a few lines later, while discussing “semantic contagion,” Hacking argues that the latter concept should be understood as a form of suggestion (p. 256). This is noteworthy since semantic contagion forms part of his own account of multiple personality, namely through the framework of “making up people” (p. 239). These ambiguous statements raise the question of how Hacking’s ontological project can be understood in terms of suggestibility. I argue that Hacking’s understanding of suggestibility is both psychological and logical, and show how this concept illuminates Hacking’s historical ontology and its continued relevance in contemporary psychological debates.