A posteriori, a priori: Terms used to refer to whether an assertion is dependent on experience (a posteriori) or independent of experience (a priori). For example, if one observes creation and sees in it an organized pattern, it might be concluded a posteriori (i.e., on the basis of observing creation) that God exists as its cause. However, if God's existence can be proved on some basis prior to sense experience, then the existence of God is argued a priori.1
1. Stanley J. Grenz, David Guretzki & Cherith Fee Nordling, Pocket Dictionary of Theological Terms (Downers Grove, IL: InterVarsity Press, 1999), p. 7.