Cognoscendi and Nature
...in the case of true or Christian natural theology, Scripture cannot be the principium cognoscendi. Alsted, who developed one of the more massive treatises on natural theology in the era of early orthodoxy, counts nature as the principium of natural theology, Scripture as the principium of supernatural theology.
Richard A. Muller, Post-Reformation Reformed Dogmatics: The Rise and Development of Reformed Orthodoxy; Volume 1: Prolegomena to Theology, 2nd ed. (Grand Rapids, MI: Baker Academic, 2003), 436.