The similarities between William James’ Stream of Consciousness and Henri Bergson’s La durée réelle have often been noted. Both emphasize the fundamentally temporal nature of our conscious experience and its constant flow. However, in this article, I argue that despite surface similarities between the OP theories, they are fundamentally different. The ultimate reason for the differences between the theories is that James believed that we should reject psychological explanations that depend on synthesis within the mental sphere. This is because such (...) explanations are incompatible with empiricism. Instead, we should look to the physiological mechanisms underpinning mental states. In contrast, Bergson was an adamant defender of a form of mental processing which he called qualitative synthesis. Duration itself, for Bergson, is a form of qualitative synthesis. However, in 1906, less than five years before James died, Bergson convinced him to change his mind. This results in a huge shift in James’ thought. Unless we understand how far apart James and Bergson were prior to this shift, we will not have a proper picture of the full influence of Bergson on James’ thought, nor of the major changes to James’ philosophy that occurred near the end of his life. (shrink)