Relying on two works - 'Matter and Memory' and a study on dreams - the author traces implications of Bergson's metaphysical assumptions. They seem to support not only Bergson's epistemological tenets but also his neurobiological hypotheses. The entire structure of Bergson's philosophy is reviewed in this process - the conception of duration, critique of the spatial projection of mental imagery, the theory of surface and deep ego. Bergson's assumptions combine to make traditional epistemological debates on the character of mental images obsolete. They put in new light mechanisms of remembering, the difference between perception and recollection, the distinction between habitual memory and purposeful recollecting. In the end a new reading of Bergson's metaphysical assumptions is offered, in which the concept of unconsciousness plays a great role and the anti-reductionist stance seems to be vindicated. The author acknowledges his indebtedness to Barbara Skarga and her book 'Czas i trwanie' [Time and duration].