Locke attacks both the view that we have any innate principles (for example, the whole is greater than the part, do unto others as you would have done unto you, etc.) as well as the view that there are any innate singular ideas (for example, God, identity, substance, and so forth). The main thrust of Locke’s argument lies in pointing out that none of the mental content alleged to be innate is universally shared by all humans. He notes that children and the mentally disabled, for example, do not have in their minds an allegedly innate complex thought like “equals taken from equals leave equals”. He also uses evidence from travel literature to point out that many non-Europeans deny what were taken to be innate moral maxims and that some groups even lack the idea of a God. Locke takes the fact that not all humans have these ideas as evidence that they were not implanted by God in humans minds, and that they are therefore acquired rather than innate.
Locke is very careful to refrain from speaking as if opinion is "mere opinion;" he is not a skeptic and does not believe that science is futile. On the contrary, he is very eager to claim in the last chapters of the Essay , that we should be satisfied with this level of certitude and that we should continue collecting scientific data with gusto. Gaining a better and better opinion of the world is a worthy goal, and one that he shares. He does ask, however, that we be aware that as good as our opinions become, they are never going to reach the level of knowledge.
Longer essays may also contain an introductory page that defines words and phrases of the essay's topic. Most academic institutions require that all substantial facts, quotations, and other porting material in an essay be referenced in a bibliography or works cited page at the end of the text. This scholarly convention helps others (whether teachers or fellow scholars) to understand the basis of facts and quotations the author uses to support the essay's argument and helps readers evaluate to what extent the argument is supported by evidence, and to evaluate the quality of that evidence. The academic essay tests the student's ability to present their thoughts in an organized way and is designed to test their intellectual capabilities.