Consciousness is constantly changing. Even though consciousness is continuous and can be characterized as a steady stream from birth to death, it is also constantly changing. James quoted Heraclitus’s aphorism about the impossibility of stepping into the same river twice. For James, the same is true for conscious experience. One can never have exactly the same idea twice because the stream of consciousness that provides the context for the idea is ever-changing.
Consciousness is selective. Some of the many events entering consciousness are selected for further consideration and others are inhibited. James (1890/1950) writes:
We see that the mind is at every stage a theatre of simultaneous possibilities. Consciousness consists in the comparison of these with each other, the selection of some, and the suppression of the rest by the reinforcing and inhibiting agency of attention.
Finally, and perhaps most important, consciousness is functional. This idea permeates all of James’s writ- ing, and it is the point from which the school of functionalism developed. According to James, the most important thing about consciousness—and the thing the elementists overlooked—is that its purpose is to aid the individual in adapting to the environment. Here we see the powerful influence of Darwin on early U.S. scientific psychology.
Consciousness, then, is personal, continuous, constantly changing, selective, and purposive. Very little in this is compatible with the view held by Wundt or the structuralists. James (1890/1950) reached the following famous conclusion concerning consciousness: