How did Henri Bergson challenge psychophysiological parallelism?

Henri Bergson challenged the doctrine of psychophysiological parallelism—which posited that every psychological fact is strictly determined by a corresponding physiological fact—by analyzing the phenomenon of aphasia in his work Matter and Memory.1

Parallelism suggested that a brain lesion should destroy the underlying psychological power itself. However, Bergson observed that aphasic patients often retain the ability to understand language and know what they wish to communicate, despite being unable to speak. He argued that this proves the memory or mind is not actually lost; rather, the patient has lost only the specific bodily mechanism required to express that mental state.1

From this, Bergson concluded that the mind is independent of the body, utilizing it as a tool to carry out its purposes, rather than being a mere byproduct of physiological processes.1