Hypothesis

He believes that if he discredits all belief, he can disregard falsified beliefs and mitigate their influence on the “good” or true beliefs that he strived for.
The action of doubting demonstrates that there is a doubter, therefore because he thinks, he is.
Substance dualism, that his mind and body that differentiate as a thinking substance and a physical substance.
After going through methodological doubt, ensuring that any idea depredations as true has already passed the test of being clear.
Yes, as senses are notorious for misleading individuals, Descartes reasoning is more trustworthy.
Rationalism and Empiricism differ by justifying existence in two very different ways- one using sensory experiences and the other using reasoning as the basis of understanding.