The constant flux and caprice of mental events do not admit of the establishment of stable experimental conditions.

Mental events, it is said, are not passive happenings but the acts of a subject.

Series of syllables which have been learned by heart, forgotten, and learned anew must be similar as to their inner conditions at the times when they can be recited.

Mental states of every kind, - sensations, feelings, ideas, - which were at one time present in consciousness and then have disappeared from it, have not with their disappearance absolutely ceased to exist.

Of course, a movie is in constant flux.

Nothing is eternally stable, and even Kansas isn't really in Kansas anymore. The earth is in a constant state of flux.