Descartes philosophy of 'How much We Know'. How can you be sure as Descartes wanted to be about what you know?

Descartes epistemology rests heavily upon his methods of doubt and foundationalism. He insists that the customary routes to knowledge, "the senses," are unreliable therefore we have good reason to doubt knowledge gained in such a fashion. Obviously he doesn't expect us to reject all we know, "sincere doubt," instead we must employ hypothetical doubt when pertaining to true knowledge. Believing as Plato, that sense perception and reason deceive us and that man cannot have real …

…Jesus, as my parents chose what to believe for me. Till I hit my teenage years, I wondered about this same topic. Are we being manipulated by society? the media? our school, our Government Etc. I pondered, and came to realize that Descartes was right, that authorities do actually make a major impact to our minds as they basically forced us to believe in something we did not know whether it was right or wrong.