 A pivotal thinker in this transformation is René Descartes (1596–1650 CE). In his Meditationes, after “proving” that the matter (res extensa) and mind (res cogitans) are different substances (i.e., forms of being existing independently), the question of the interaction between these substances becomes an issue. The malleability of wax is for Descartes an explicit argument against influence of the res extensa on the res cogitans (Meditationes II, 15). The fact that a piece of wax loses its form and other qualities easily when heated, implies that the senses are not adequate for the identification of objects in the world. True knowledge thus can only be reached via “inspection of the mind”. Here the wax metaphor that for more than 1500 years was used to explain sensory impression is used to argue against the possibility to reach knowledge via the senses. Since the essence of the res extensa is extension, thinking fundamentally can not be understood as a spatial process. Descartes still uses the terms “form” and “idea” in the original scholastic non-geometric (atemporal, aspatial) sense. An example is the short formal proof of God’s existence in the second answer to Mersenne in the Meditationes de Prima Philosophia