Why did Henri Bergson argue that aphasia does not prove memory is stored in the brain?

In his work Matter and Memory, French philosopher Henri Bergson challenged the prevailing doctrine of psychophysiological parallelism, which posited that every psychological state is strictly determined by a corresponding physiological state in the brain.1

Bergson argued that aphasia—the loss of the ability to use language—does not prove that memory is stored within the brain. He observed that aphasic patients often retain the ability to understand what others say and know what they themselves wish to communicate, while suffering no paralysis of their speech organs, yet they remain unable to speak.1

From these empirical facts, Bergson concluded that the condition does not represent a loss of memory itself, but rather an impairment of the bodily mechanism required to express that memory. Consequently, he argued that the mind or soul is independent of the body, utilizing it merely as an instrument to carry out its purposes.1