“A new calumny against me, have my rivals lately devised, because I write upon the dialectic art; affirming that it is not lawful for a Christian to treat of things which do not pertain to the Faith. Not only they say that this science does not prepare us for the Faith, but that it destroys faith by the implications of its arguments. But it is wonderful if I must not discuss what is permitted them to read. If they allow that the art militates against faith, surely they deem it not to be science (_scientia_). For the science of truth is the comprehension of things, whose _species_ is the wisdom in which faith consists. Truth is not opposed to truth. For not as falsehood may be opposed to falsity, or evil to evil, can the true be opposed to the true, or the good to the good; but rather all good things are in accord. All knowledge is good, even that which relates to evil, because a righteous man must have it. Since he should guard against evil, it is necessary that he should know it beforehand: otherwise he could not shun it. Though an act be evil, knowledge regarding it is good; though it be evil to sin, it is good to know the sin, which otherwise we could not shun. Nor is the science _mathematica_ to be deemed evil, whose practice (astrology) is evil. Nor is it a crime to know with what services and immolations the demons may be compelled to do our will, but to use such knowledge. For if it were evil to know this, how could God be absolved, who knows the desires and cogitations of all His creatures, and how the concurrence of demons may be obtained? If therefore it is not wrong to know, but to do, the evil is to be referred to the act and not to the knowledge. Hence we are convinced that all knowledge, which indeed comes from God alone and from His bounty, is good. Wherefore the study of every science should be conceded to be good, because that which is good comes from it; and especially one must insist upon the study of that _doctrina_ by which the greater truth is known. This is dialectic, whose function is to distinguish between every truth and falsity: as leader in all knowledge it holds the primacy and rule of all philosophy. The same also is shown to be needful to the Catholic Faith, which cannot without its aid resist the sophistries of schismatics.”[468]