The imaginary is rightly called a power of contestation and of creation. Insofar as such a power wields images drawn from practical processes and dry abstraction, it is assumed from the first that we are able to evoke such images. This faculty, which can be compromised by certain developments and types of culture, must first of all be named. Let us call it, as Charles Fourier might have done: image-evocative power. By postulating its existence, we are acknowledging the fact that we notice it, and acknowledging the links that attach it to Nature. But we are also noticing the things that threaten it in an era of technology which tends towards analytical reduction and operational formalism.