Part One: Doctrinal, Apologetic, and Pedagogical

89. - Rationale of the order. By a rationale not unlike that by which they are accustomed in schools of law to distinguish doctrine and jurisprudence - doctrine, I say, which is occupied with the scientific exposition of laws, with principles and ends added; and jurisprudence, which proposes the correct estimation of human facts according to the laws - we have divided our moral treatment into two parts, of which we have called the former doctrinal, apologetic, and pedagogical, and the latter casuistic.

The former part, insofar as it is doctrinal, expounds the rules which must be laid down for that natural sexual appetite which we have already come to know anthropologically; it indicates the laudable or necessary ends toward which either the use, or the moderation, or even the restraint of that appetite can be directed; that is, in sum, it examines the virtue of chastity, its nature, excellence, and duties according to the diverse condition of human beings.

Insofar as it is apologetic, it protects and vindicates the moral rules of the Catholic Church.

Insofar as it is pedagogical, it adds counsels by which those ends may be attained more surely, more easily, and more fully; or it shows itself solicitous about the manner in which the virtue of chastity is to be cultivated, perfected, and restored.

Therefore it is divided into two sections, of which one treats the good or virtue of chastity, and the other treats the cultivation of chastity according to the various states and conditions of persons.

In the casuistic part, however, abstracting more from the final rationales of acting, we turn rather to defining what is lawful and unlawful and to weighing the varying gravity of sins. These explanations are useful for the prudent formation of the mind and cannot be neglected by a penitential judge; but they furnish to a man only an inadequate norm of acting, one which must be perfected by the persuasions of the former part, so that he may be rendered worthy of the Christian vocation.

By the former part, the confessor will chiefly be assisted in sustaining the person of teacher and physician; by the latter, he will be instructed to exercise rightly the office of judge. Yet the two parts could not be so separated that the latter would have nothing doctrinal to propose, since the intrinsic rationale of the replies must be given, and especially since the intrinsic and grave malice of lust must be discussed there; and since we must be solicitous about the manner of treating this argument fruitfully in the tribunal of penance.