What does the term "a priori" refer to?

The term "a priori" refers to reasoning or knowledge that is derived from theoretical deduction rather than from empirical observation or experience. It is often contrasted with "a posteriori," which refers to knowledge gained through experience. A priori knowledge is considered universal and necessary, often involving concepts that can be understood through logic and reason alone, independent of sensory experience.

In philosophical discussions, a priori knowledge includes mathematical truths and logical principles that do not require observation or experimentation to validate. Understanding this concept is essential, as it highlights the distinction between different sources of knowledge and reasoning processes.