More specifically, we see both intellectual and moral progress not as a matter of getting closer to the True or the Good or the Right, but as an increase in imaginative power. We see imagination as the cutting edge of cultural evolution, the power which - given peace and prosperity - constantly operates so as to make the human future richer than the human past. Imagination is the source both of new scientific pictures of the physical universe and of new conceptions of possible communities. It is what Newton and Christ, Freud and Marx, had in common: the ability to redescribe the familiar in unfamiliar terms.