Representation (Latin repraesentatio, French représentation) is not a technical term for Descartes. He offers no definition of it and has no explicit theory of it. While representation is a central concept in today's theory of mind (along with intentionality and consciousness), early modern theories of mind center on the cognitive faculties (intellect, imagination, memory, senses). That does not mean the concept of representation plays no role in Descartes’ theory of mind; it simply means that we have to do some rational reconstruction to determine what that role is.
In the seventeenth century, repraesentare and représenter mean many things, but their chief meaning is to present something or make something immediately available. One can represent a gift to a friend or a sum of money to a creditor. But the verbs can also mean making something present by way of a proxy or substitute for the thing itself. In this latter sense, a lawyer represents his client. Most cases of philosophical interest fall somewhere in between the two: when an actor represents Henry VIII on the stage, there is a sense in which he is making Henry VIII present to the audience, although he is just a proxy or substitute for Henry himself. The ambiguity found in this case animates discussions of representation in the theory of mind: mental states make objects, facts, and states of affairs present to the mind, but do they do so by means of proxies or substitutes for those objects, facts, and states of affairs? If they do employ proxies, what are the epistemological and metaphysical consequences? And whether or not they employ proxies, how does a mental state manage to represent something distinct from itself? These are questions an account of mental representation must answer.
2.Epistemology of Mental Representation
The question whether Descartes was a “direct realist” or an “indirect realist” has occupied commentators since Reid in the eighteenth century cast him in the latter role. At issue is whether thought (including both sensory and intellectual perception) involves mental representations that mediate epistemologically between mind and world. Direct realists insist that the mind is in immediate epistemic contact with its object.