On account of the heresies, therefore, the toil of discovery must be undertaken; but we must not at all abandon [the truth]. For, on fruit being set before us, some real and ripe, and some made of wax, as like the real as possible, we are not to abstain from both on account of the resemblance. But by the exercise of the apprehension of contemplation, and by reasoning of the most decisive character, we must distinguish the true from the seeming.