Bergson's thesis is that Darwinian and Lamarkian evolution are only half the story and that there is a creative urge inherent in life that defines the direction of evolution. It is distinguished from Creationism in that his system does not posit and eschaton or final perfect form, nor an external agent (God).
It has some similarity with biologist Rupert Sheldrake's theory of morphic fields. In his theory, there is an energy field (as yet undetected by modern physics) that controls the shape of organic molecules, i.e., one protein is shaped one way and the same collection of atoms gets shaped another way under the same pH and temperature.
Aldous Huxley mentions Bergson's theory of consciousness several times in his writings. Bergson thinks that consciousness pervades everything, and that intellect serves as a filter that presents only what is comprehensible to mental categories. This has several implications. One is the possibility for a monistic metaphysic. The other is that it leaves open the possibility of perceiving an alternate reality (what excited Huxley).
Chapter 3 is about his metaphysics, which are not very clearly expressed. There appear to be avenues unexplored by him. What are the consequences of matter being infused with consciousness? Magic? Why is it that intellect and geometrical thinking is what produces objects in perception? What is the mechanism.
What does have value is his theory that chaos is not the absence of repeatability, but is a stochastic process that can be understood as an aggregate of individual "wills." This is used to support his vital theory of evolution. That each organism "wills" its variation in seemingly random fashion, but at a higher order, it produces the regularity of genera.
Chapter 4 is a critique of various philosophic systems after establishing his "cinematographic" theory of perception. His basic point is that matter is in continual flux, yet we are only able to perceive it as a sequence of discrete states, hence the illusion of permanence.