Descartes take to the question “What can I know?”

How do we acquire knowledge? What approach does Descartes take to the question “What can I know?” How does this approach fit with his idea of doubt? How would George​‌‍‍‍‌‍‍‌‍‌‌‍‍‍‌‍‌‌‌‍​ Yancy and Derrick Jensen each critique such an approach? With whom do you agree and why? Be specific, referring to the arguments and phrases the person(s) with whom you agree are using​‌‍‍‍‌‍‍‌‍‌‌‍‍‍‌‍‌‌‌‍​.