What does parentheses or brackets stand for?

Answer 1

These markings generally stand for information that is connected to the central idea of the paragraph but not central to the issue. Such information would be birth dates and death dates of a particular person in a paragraph about what the person postulated, an aside comments (just like this one, not germaine to your answer) or even further links and information that are not immediately necessary to the writing. This information is either common knowledge or something that does not rate a footnote to the writing. A footnote is necessary when one is quoting the subject or copying a section to prove a point. Snippets of information that would be useful additions such as a pair of dates fpr a writer. Since the birth and death date of Walt Whitman is available on EVERY site mentioning his name, brackets or parentheses are appropriate for the information.