The problem of Apriori knowledge in Descartes and Kant

Descartes stated that he had been mistaken by accepting the knowledge as truth which obtained. He developed methodological doubt in order to purge himself from his delusions and to access clear and distinct knowledge. At the end of the methodological doubt he claimed that he find clear and distinct proposition which is "I think, therefore I am." Important point is "I" here. "I" refers to the substance of thought. He sees the substance of extension (belonging to the objects) as the opposite of thought. Descartes intends to distinguish between thought and object by introducing dualism. There can be no confidence in the knowledge of the object that is not clear, even if it is distinct. He claims that the innate ideas remains unchanged in the human mind as the main source of knowledge. He defends the innate ideas that are clear and distinct to the human mind. The innate ideas found in the human mind have been put in by a non-deceptive God itself. With the sentence above, Descartes based its philosophy on metaphysics. On the other hand, Kant criticizes metaphysics of Descartes as an antinomy. According to Kant, fundamentals of knowledge should not contain metaphysical elements. As Descartes has done, the source of the knowledge should not be searched. According to Kant, the knowledge that needs to be investigated is "how". Kant's idea about the process of obtaining information: intuition forms (space and time) and categories of understanding (total of twelve in four main headings) work together when human beings perceive phenomena. Human beings can obtain knowledge is the field of phenomena, the other side cannot. According to Kant, intuition forms and categories of understanding are found in human beings as synthetic a priori. The attitude of Descartes is a rationalist attitude, Kant's attitude is a Transcendental idealist against knowledge. The aim of this study is to clarify these differences in the approach of knowledge and shows that reason of difference in a priori knowledge.