John Locke
Since there aren't really any characters in this philosophical work, John Locke takes the place of a character. He is the one presenting all of the ideas and proving why they are correct. He would also take the place of a protagonist because he is the one that drives the treatise and tells all of his ideas that will help influence what is yet to come.
Education
Education is also one of the characters because it is what all of John Locke's ideas are based around. In this particular treatise, we learn of how people are educated throughout their life, so we consider it a noun, or a character. Since an idea or way of doing things can be personified, education can be a character in this essay.