 What exactly counts as experience? If by “experience” we mean just perceptual experiences, justification deriving from introspective or memorial experiences would count as a priori. For example, I could then know a priori that I’m thirsty, or what I ate for breakfast this morning. While the term “a priori” is sometimes used in this way, the strict use of the term restricts a priori justification to justification derived solely from the use of reason. According to this usage, the word “experiences” in the definition above includes perceptual, introspective, and memorial experiences alike. On this narrower understanding, paragons of what I can know a priori are conceptual truths (such as “All bachelors are unmarried”), and truths of mathematics, geometry and logic.