At every stage of Descartes’s argument in the Meditations, there are ontological implications: the mind’s independence of sensory perceptions (perceptions whose reliability is ultimately upset by the possibility that he is dreaming), the literally unimaginable sort of thing that a physical object such as a piece of wax must be, the existence of a veracious God, who provides a guarantee for the reliability of reason, and finally the existence of a physical world consisting of extended things. Arn