First, Deleuze redefines the simulacrum, not as a secondary image of life, but as life itself. That is, there is not a full and present life, sufficient unto itself and fully actualized, which then relates to what is not itself by forming images or representations. So Deleuze does not begin from a mind or consciousness that must somehow come to know or find its outside world; he does not begin philosophy from the question of ‘what can we know?’ or 'how accurate are the images we have of the world?’ He does not begin from human life or the life of the organism and then ask how consciousness came into being, for he does not regard life as a set of things or organisms that then perceives. Rather, life is perception, or a virtual power to relate and to image. There could not be mind or consciousness, for example, without the connection between the brain, the body, the body’s organs and external stimuli. These connections among the bodily parts that form both the human organism, and the human organism’s relation to the world, are perceptions or images. Evolving life is nothing more than a web of perceptive responses–cells responding and adapting to other cells to form simple life forms, those life forms responding to or 'perceiving’ environments. There is not a mind or life and then the perception of images, for life is imaging, a plane of relations that take the form of 'perceptions’ precisely because something 'is’ only its responses. Before there are actual terms–'mind’ on the one hand, 'world’ on the other–there is a potential for relation, and the relations for Deleuze are best described as 'images’.
— Claire Colebrook, Deleuze: a guide for the perplexed