John Locke proposed the concept of "tabula rasa". What does this term mean, and in which of his works did he introduce it?
1
"Blank slate"; "An Essay Concerning Human Understanding" (1690)
2
"Innate ideas"; "Two Treatises of Government" (1689)
3
"Natural rights"; "Some Thoughts Concerning Education" (1693)
4
"Social contract"; "A Letter Concerning Toleration" (1689)