If duration is the continuous interpenetration of past and present in a single living flow, then memory is not what standard psychology says it is.
The standard picture of memory is essentially spatial: the past is a storehouse of recordings, and remembering is retrieving one of those recordings and playing it back in the present. This is the library model of memory. You have experiences, they get stored (in engrams, or traces, or some neural equivalent of files), and when you remember, you look up the file and read it.
Bergson argues that this picture is wrong, and his argument in Matter and Memory (1896) is among the most original pieces of philosophy he produced. His key move: the past is not stored somewhere. It is preserved in its entirety, always. The past does not disappear and then get retrieved. It persists, in its wholeness, and what memory does is not retrieval but actualization: bringing a particular aspect of the persisting past into contact with the present.
The analogy he uses: the present is the cutting edge of a cone. The apex of the cone (the tip) is the present moment of action and perception. Behind the apex stretches the body of the cone: the entire past, preserved in its wholeness, with the most recent past closest to the tip and the most distant past at the widest end. Memory is not going to a filing cabinet. It is the whole cone pressing forward into the present, with different layers more or less available depending on the degree of tension or relaxation of attention.
What this means for consciousness is striking. For Bergson, consciousness is not primarily about the present moment. It is temporal thickness: the past pressing forward into the present, shaping perception and action in ways we are mostly not aware of. The present moment, stripped of its temporal thickness, would not be experience at all. It would be a knife-edge with no content.
This anticipates, in philosophically precise form, what contemporary neuroscientists and psychologists call predictive processing: the finding that the brain does not simply process incoming sensory data but actively predicts what is coming based on prior experience, and that what we experience as perception is largely the brain's model rather than raw sensory input. Memory and perception are not separate systems in the brain: the past constantly shapes what we see in the present. Bergson had the philosophical structure of this argument in 1896, decades before the neuroscience.
For consciousness more broadly, Bergson argues that the standard picture of the mind as a kind of mechanism with discrete states is wrong for exactly the reason that the clock picture of time is wrong: it spatializes something that is intrinsically temporal and flowing. Consciousness is not a series of states. It is a continuous movement, and analyzing it into discrete states destroys what is most essential about it: its temporal continuity, its creativity, its irreducibility to any fixed description.