How did aphasia influence Henri Bergson’s theory of memory?

Henri Bergson’s study of aphasia—the loss of the ability to use language—was central to his development of the theory of memory presented in his 1896 work, Matter and Memory.1

At the time, the prevailing doctrine of psychophysiological parallelism suggested that every psychological state was strictly determined by a corresponding physiological fact, implying that brain lesions should destroy the psychological power itself. Bergson challenged this by observing that aphasic patients often understood what others said and knew what they themselves wanted to express, despite being unable to speak.1

Because these individuals suffered no paralysis of the speech organs yet remained unable to articulate their thoughts, Bergson argued that the memory itself was not lost. Instead, he concluded that the brain lesion had merely damaged the bodily mechanism required to express that memory. This led Bergson to the philosophical conclusion that the mind, or soul, is independent of the body and utilizes it as a tool to carry out its purposes.1