A priori truths, in philosophy, refer to types of truths that are known or can be known independently of experience or empirical evidence. These truths are considered to be fundamental and self-evident, relying solely on reason and logic for their understanding and establishment. The term "a priori" is a Latin phrase meaning "from the earlier," suggesting that these truths precede and serve as the foundation for any empirical knowledge acquired through observation.
A priori truths can be considered to be universal and necessary, holding true in all possible worlds or circumstances. They are often contrasted with a posteriori truths, which are derived from experience, sensory perception, or empirical data. Unlike a posteriori truths, a priori truths are not contingent upon specific instances or experiences but are believed to be applicable universally and necessarily.
Examples of a priori truths include logical statements such as "all triangles have three sides" or "a whole is greater than any of its parts." These truths are not based on specific observations of triangles or wholes but can be understood and proven through pure reason.
Immanuel Kant, a prominent philosopher, distinguished a priori truths as the synthetic a priori, where they are reflective of our understanding of the world by adding information not contained in the subject (such as mathematical principles), and the analytic a priori, where they are self-evident and true solely based on the definition of the subject (such as the principle of identity). A priori truths continue to be central to understanding knowledge, reason, and the limits of our understanding in philosophy.
