The importance of this discovery and its interpretation in Desgabets’s thought is paramount, since he believed that because of it, the way had been opened at last to lay the foundations of a true philosophy. Based on Descartes’s conception of matter, and his consequent discovery of the true nature of sensible qualities, Desgabets concluded that our perception of sensible qualities and sensible objects does not constitute knowledge of the true state of exterior things. In fact, sensible qualities