Henry begins his own response with a crucial distinction. Someone may be said to be a doctor in two different ways: because he is capable of teaching or because he has the office of teaching (officium docendi). In the first sense, one is a doctor by dint of his state or condition (habitus) of knowledge and consequent ability to teach. Such a habitus is not dismissed by the act of sinning, any more than it is acquired by virtuous action—though it may be said (following Averroes in his commentary on Book vii of Aristotle’s Physics)26 that the habitus of virtue disposes one to the acquisition of knowledge. In the passage under discussion Aristotle had explained that knowledge can be acquired only when the soul settles down from the restlessness natural to it. Commenting on this passage, Thomas Aquinas (writing at Paris in 1271) noted that understanding, i.e., speculative thought, and prudence, i.e., practical reason, come to the soul through the rest and abating of corporeal motions and sensible affections.27 The obvious inference is that moral virtue, whereby the restless passions are controlled, is therefore in a sense conducive to intellectual virtue. Through its practice are created the best possible conditions in which knowledge can be acquired. To adopt a metaphor used by Averroes, the process involved is like polishing metal so that it might become a mirror and receive light.28
But Henry is far more interested in the idea that the state of knowledge, once it actually is acquired, is there to stay, and cannot be lost through immoral behavior. In this sense, a man who is evil and a sinner can be called a doctor of the science of theology, for he is able to have correct doctrine just like the righteous man, and indeed he may he better educated than the righteous man in respect of the relevant habitus of knowledge. Thus he is a doctor of another person by dint of his possession of the habitus of this science, and may be compared to the craftsman (artifex) who practices his skill in accordance with the habitus of that art. Aristotle is quoted as saying that it is not necessary for the craftsman to be morally virtuous in order to exercise his craft.29 In order that an artisan might make good knives, Henry elaborates, he requires not moral virtue but mere proficiency in the art of knife making. The “perfection of the art” of knife making is simply— good knives. The inference is that the good doctor (on Henry’s first definition) does not have to be a morally good man.
The second sense in which someone may be said to be a doctor relates to the audience’s reception of the teacher rather than his mental state and personal abilities. On this definition, a teacher is someone who holds the office of public teaching (officium publice docendi). For this, the approval of the taught is essential. Here the analogy is with the doctor of medicine rather than with the craftsman. No matter how experienced (peritus) a medical doctor was in his profession, or however good were the medicines he dispensed, he would not be acceptable to his patients if he was not disposed to make them well. So, if he were irascible, and thereby provoked all his patients to anger, which inevitably would endanger their health, he would not be permitted to practice. Likewise, with the doctor of theology: no matter how skilled (peritus) he may be, if he cannot exercise his officium doctoris without imperiling his audience, then he should by no means be permitted to teach or to be a teacher of theology. It is necessary to have both the habitus of knowledge, as explained above, and a good reputation ( fama bone vitae). Therefore, in the doctor who de iure and ex officio can and ought to teach this science, two things are required: knowledge (scientia) by dint of which he can teach, and a life by dint of which he can teach wholesomely.
Henry proceeds to develop this argument by enlisting the aid of the Aristotelian theory of causality and instrumentality. A doctor of sacred Scripture is, as it were, an instrument and organ (instrumentum et organum) of the word of God,30 inasmuch as he teaches the faithful with regard to their spiritual health or profit(utilitas). Hence the Gloss on Matthew 3:3 (“a voice crying in the wilderness . . . ”) identifies John the Baptist as the voice and Christ as the Word which cries in John.31 For just as with an instrument or organ, the formal disposition and its own constituent material is determined by its objective or end (finis) and the material in respect of which it functions. At this point Henry draws on the second book of the Physics, where Aristotle had explained that certain things are required in order that a given product can come into being, but the product comes into being on account of some end, and not on account of those requirements.32 Aristotle had used the example of a saw, which is designed to carry out something and for the sake of something; this end, however, cannot be achieved unless it is made of the right stuff. If we are to have a saw and perform the operation of sawing, it must be made of iron. As Averroes puts it, the action of sawing cannot be achieved except on account of the form and material of the saw.33 Thus, to return to Henry, the end determines the material, the end being impossible to attain without the necessary material. Henry gives an elaborate version of the “saw” example and makes his own application of the underlying doctrine. In order that a saw can cut straight through tough wood, it must be made of strong and firm metal and it must have teeth: that is to say, the material out of which the tool is made (strong metal) and its formal disposition, pattern, or shape (its teeth) are determined by its end or objective (cutting the wood) and the material on which it works (the hard wood). The material with which the teacher of holy Scripture has to work are the faithful whom he must instruct; the end toward which he works is their own (spiritual) health or profit and that of others through instruction; the material employed in this work is his knowledge; the formal disposition necessary in himself in order that he might realize his objective is a holy life—he himself must first do the things which he teaches others to do.
Any unlearned man who usurps the office of teaching and does not announce Christ with sincerity deserves utter damnation, Henry continues. The saw, if it is made of soft metal, cannot divide the wood. Likewise, an individual who is learned but unjust in his behavior may be able to instruct the faithful, but is quite unable to “enform” or shape them in holy life or to maintain them therein. As Chrysostom says on Matthew 5:13 (“you are the salt of the earth”), the doctor should be adorned with all the virtues, so that he is able to prompt the lazy and sluggish to perform good works, by his example rather than by mere words.34 The good manner of life of a priest may, irrespective of words, maintain the holy in sanctity by its example, but without words he cannot lead the ignorant to knowledge of the truth. On the other hand, words, without the example of good behavior, can lead a certain ignorant person to the knowledge of truth, but without the example of good behavior such a one could not remain in faith or holiness. A priest whose life does not match his words is a source of scandal. Even though he may perhaps lead the good to the knowledge of truth, he will tend rather to keep bad people away from the truth. As St. Gregory says, the magisterium of pastor is confounded when one thing is done and another is taught; consequently, when someone’s life is despised it follows that his preaching will be condemned.35 To which Henry appends that Aristotelian saw. Just as, if a saw is without teeth it cannot directly attain its end in cutting, so no doctor who is not “enformed” by familiarity with holiness can wholesomely teach others. It must be said, therefore, that the proper teacher of this science must not only be competent to teach the truth but also be good and just, so that he should enact the same. Acts 1:1 tells how “Jesus began to do and to teach,” which the Gloss explains as meaning that the good teacher should first do and then teach, in that order, so that his word is not destroyed by his work.36 On this argument, then, the sinner or unjust man cannot be a doctor of holy Scripture.
However, there are degrees of prohibition, it would seem, some errant teachers being more relevantly sinful than others. For