Descartes (Meditation One)
If Descartes’s aim is to find certainty, why does he proceed by doubting as many things as he can?
He feels that as long as he goes on believing his old beliefs, laziness and habit will block him from receiving any truths. He feels that if he regards his beliefs in the same way as he does any falsehoods he can remain unbiased when judging information and only then will he receive real truths.
What reason does he give for doubting that the senses give knowledge?
That a man asleep can have a realistic dream that he is having the same experiences as a man that's awake.
What does the experience of “dreams” show us concerning the senses?
He talks about how real dreams appear even though they are proven to be deceiving. And if one can be deceived in a dream by all of their senses can they not also be deceived in reality by some supernatural demon. He says hypothetically that God may not have created earth, shapes, etc. and everything that we sense could be a form of deception.
Why can he doubt even that 2=3 = 5.
He talks about the fact that he sometimes doubt others who claim to have the most perfect knowledge. And if that can be the case for them can't it also be possible for him to be wrong about “obvious” truths. Also, if one may feel that if God's goodness would stop him from being deceived SOME of the time, wouldn't it stop him from being deceived ALL of the time since he is clearly deceived some of the time. Basically he is acknowledging the fact that he could be wrong.