This article examines Giovanni Pico della Mirandola's detailed reaction against the condemnation of some of his famous Theses by a papal commission, through a careful reading of his Apology of 1487. This text, which was never studied in detail and still waits for a critical edition, reflects Pico's remarkable familiarity with the scholastic thinkers up to his own times. As part of his self-defense, Pico deals with the relation between opinions and faith, probable knowledge and certain truth, philosophy and theology, thus developing a method for examining theological opinions. To some extent, this method was based on the classical notions of probabile and veri simile, coming from the ancient Academic skeptics, which Pico knew from Cicero and Augustine. This, I argue, was part of Pico's humanist theology, his solution for the authority crisis of his time and for what he regarded as an unsolved tension in scholastic philosophy between human opinions and the revealed truth of faith.