From the certainty resulting from the existence of thought being, Descartes stepped forward in the existence of God. He defended that existence by giving evidence based on the ontological argument of Anselm and evidence on the first cause, which inevitably produces in the idea thinker of God. Skull Breast cancer warrior all over printed hoodie. Thus, in attaining the existence of God, Descartes also reached the reality of the physical world through God, who did not deceive the mind thinking with perceptions which are illusions. Therefore, the external world that we perceive must exist. Thus, Descartes falls back into acceptance of what is clearly and specifically perceived by us.