In his Meditations on First Philosophy, Descartes strives first and foremost to provide an infallibly justified foundation for the empirical sciences, and second to prove the existence of God. I will focus on the first and second meditations in my attempt to show that, in his skepticism of the sources of knowledge, he fails to follow the rules he has set out in the Discourse on Method. First I claim that Descartes fails to draw the distinction between pure sensation and inference, which make up what he calls sensation, and then consider the consequences of this failure to follow his method. Second, I will show that in his treatment of thinking Descartes fails to distinguish between active and passive thinking.
Although he succeeds in showing that he is aware of thinking (and therefore at least a passive thinker), from which it follows that he exists, it is possible that Descartes is no more than a passive thinker. I claim that Descartes successfully shows that he exists, that “there is thinking going on,” and that thereby “there exists a thinking thing,” but Descartes’ ‘thinking’ may only be a passive awareness of thinking; he may be separate from the active thinker required by the fact that there is thinking-going-on. I will argue that if this is the case, then Descartes doesn’t have free will. Without free will, Descartes can no longer prove the existence of God. As the foundation upon which he re-establishes his knowledge of the world depends on free will then, if my claim is true, Descartes does not succeed in finding a solid foundation for empirical knowledge, nor does he succeed in his secondary goal of proving the existence of God.
I. Pure Sensation and Inference
Descartes is determined to find an infallibly justified foundation for knowledge. He strives to find a basis for scientific reasoning so strong that it would stand even if God were to be against him. His goal is the betterment of the human condition. A useful metaphor for explaining the Cartesian system is the ‘tree of knowledge’. According to Descartes the roots of knowledge are metaphysics, to which he applies himself in the Meditations. From the metaphysics grow the physics; for they are justified by the metaphysics; the physics are the trunk of the tree. From the physics branch off mechanics, medicine and morals, the fruits of which take the form of utility, that is, applied science, medicine, and applied ethics (on an interpersonal, or international level). The development of these fruits leads to the improvement of the human condition: freedom from pain, sickness and suffering through medicine, reduction of stresses on the body and freedom from physical labour through applied science (which makes our work easier), and freedom from anxiety and mental strain through the development of applied ethics (which helps us to avoid and resolve conflicts on many levels).
Descartes uses a reductionistic method. ...