The trademark argument is an a priori argument for the existence of God developed by French philosopher and mathematician, René Descartes. In the Meditations Descartes provides two arguments for the existence of God. In Meditation V he presents a version of the ontological argument which attempts to deduce the existence of God from the nature of God; in Meditation III he presents an argument for the existence of God from one of the effects of God's activity. Descartes cannot start with the existence of the world or with some feature of the world for, at this stage of his argument, he has not established that the world exists. Instead, he starts with the fact that he has an idea of God and concludes “that the mere fact that I exist and have within me an idea of a most perfect being, that is, God, provides a very clear proof that God indeed exists.” He says, “it is no surprise that God, in creating me, should have placed this idea in me to be, as it were, the mark of the craftsman stamped on his work.” Underlying assumptions To understand Descartes’ argument it is necessary to understand some of the metaphysical assumptions that Descartes is using. Degrees of reality Descartes says, Descartes goes on to describe this as ‘transparently true’. Commenting on this passage Williams says, “This is a piece of scholastic metaphysics, and it is one of the most striking indications of the historical gap that exists between Descartes’s thought and our own, despite the modern reality of much else that he writes, that he can unblinkingly accept this unintuitive and barely comprehensible principle as self-evident in the light of reason.” In his own time, it was challenged by Hobbes who in the Objections says, “Moreover, M. Descartes should consider afresh what 'more reality' means. Does reality admit of more and less? Or does he think one thing can be more of a thing than another? If so, he should consider how this can be explained to us with that degree of clarity that every demonstration calls for, and which he himself has employed elsewhere.” To this Descartes replies: “I have … made it quite clear how reality admits of more and less. A substance is more of a thing than a mode; if there are real qualities or incomplete substances, they are things to a greater extent than modes,