Both Descartes and Locke are skeptical of the possibility of certain knowledge. Descartes went to a great school and received an education, however later on he questioned what he had learned in the institution. He thought that he gained education from “excellent books”, but he also expressed that “books should not be the basis of our knowledge” (Descartes 3). Descartes believed that there were still things that he needed to know, and questions that needed to be answered that school had not given him answers to, leading him to think that school does not designate our future. He shows his disappointment with his education by stating, “as soon as I had finished the entire course of study… I found myself involved in so many doubts and errors, that I was convinced I had advanced no farther… than the discovery at every turn of my own ignorance…” (Descartes 1) in his published treatise “Discourse on the Method of Rightly Conducting the Reason, and Seeking Truth in the Sciences”. According to Descartes, knowledge depends on absolute certainty, and he believes that there are some principles which are immediately known by the humans. These being principles which are “revealed to [us] by natural light” and “cannot in any way be open to doubt” (Descartes 1). As a result, Descartes concludes that these principles are innate.

In contrast, Locke does not believe that there is any certain knowledge. In fact, Locke says that “all ideas come from sensation and reflection; all knowledge is founded on experience” (Locke 2) in his writing “An Essay Concerning Human Understanding”. He rejects the idea of innate principles, and believes that innate ideas do not exist, otherwise they would be known to children, but they are not. (Locke 2) Being that he is an empiricist, he has this idea of the tabula rasa, meaning that “From experience: in that all our knowledge is founded, and from that it ultimately derives itself.” (Locke 2) He describes the mind at birth, at a blank state, which is later on filled with experience, not some divine natural light through which the mind can gain knowledge as we go.