Context

"The sum of cognitive elements conditioning the acquisition, validity or application of any item of human knowledge." - Leonard Peikoff

Before determining whether a particular statement is true or false, one must consider the complete context in which that statement is asserted. For example, consider the statement 2 + 2 = 4. This statement is asserted within a context, and we must consider the content of its context before we can judge whether it is true or false. Among other things, the statement's context includes the number base in which all the numbers are represented. If we assume a number base of 3 or 4, the statement is false: in base 3, 2 + 2 = 11, and in base 4, 2 + 2 = 10. However, if we assume a number base of 10 (or even 5), the statement is true (barring any other intervening facets of its context, such as nonstandard definitions of the symbols '+' and '=').

Any statement whatsoever can be rendered true or false by a suitable choice of context--as shown above, there is a context that renders false even a universally-accepted statement such as 2 + 2 = 4. Therefore, every statement (even this one!) is arbitrary until its respective context is known.