Skepticism-During the time of Plato, how did philosophers come up with the 3 major components of knowledge?

1)Formulate two questions from these topics.

-In 1981, American philosopher, Hilary Putnam, posited a skeptical scenario in which a human brain was being kept alive in a vat of chemicals and stimulated electronically to produce all of the sensations normally associated with daily life. In such a case, everything that the brain thought it knew about its environment and activities would be false. This updated variation of the ancient dream doubt is now familiar to us as the premise of the Matrix franchise of popular science fiction films.

-The French writer, Rene Descartes, added an additional dimension to the ancient skeptical scenario by positing a being that was as powerful as God but was evil instead of benign. He called this being the Evil Genius and speculated that such a being could make us believe that 2 + 3 does not equal 5 or that a square has five sides. In other words, such a being could corrupt our cognitive processes to the extent that we would not be able to know the truth of anything at all.

 

2)Response to this question

 

-During the time of Plato, how did philosophers come up with the 3 major components of knowledge? Was it from their own personal experiences? Or was it just an honest guess to their thinking? Or was it both?