The Church's social teaching proposes Principles for reflection; it provides criteria for judgment; it gives guidelines for action:

The natural law is immutable and permanent throughout the variations of history; 10 it subsists under the flux of ideas and customs and supports their progress. the rules that express it remain substantially valid. Even when it is rejected in its very Principles, it cannot be destroyed or removed from the heart of man. It always rises again in the life of individuals and societies:

Application of the natural law varies greatly; it can demand reflection that takes account of various conditions of life according to places, times, and circumstances. Nevertheless, in the diversity of cultures, the natural law remains as a rule that binds men among themselves and imposes on them, beyond the inevitable differences, common Principles.

The Principle of solidarity, also articulated in terms of "friendship" or "social charity," is a direct demand of human and Christian brotherhood. 45

Respect for the human perSon proceeds by way of respect for the Principle that "everyone should look upon his neighbor (without any exception) as 'another self,' above all bearing in mind his life and the means necessary for living it with dignity." 37 No legislation could by itself do away with the fears, prejudices, and attitudes of pride and selfishness which obstruct the establishment of truly fraternal societies. Such behavior will cease only through the charity that finds in every man a "neighbor," a brother.

"It is preferable that each power be balanced by other powers and by other spheres of responsibility which keep it within proper bounds. This is the Principle of the 'rule of law,' in which the law is sovereign and not the arbitrary will of men."

The Principle of subsidiarity is opposed to all forms of collectivism. It sets limits for state intervention. It aims at harmonizing the relationships between individuals and societies. It tends toward the establishment of true international order.

Socialization also presents dangers. Excessive intervention by the state can threaten perSonal freedom and initiative. the teaching of the Church has elaborated the Principle of subsidiarity, according to which "a community of a higher order should not interfere in the internal life of a community of a lower order, depriving the latter of its functions, but rather should support it in case of need and help to co-ordinate its activity with the activities of the rest of society, always with a view to the common good." 7

Each community is defined by its purpose and consequently obeys specific rules; but "the human perSon . . . is and ought to be the Principle, the subject and the end of all social institutions." 4

The natural law, the Creator's very good work, provides the solid foundation on which man can build the structure of moral rules to guide his choices. It also provides the indispensable moral foundation for building the human community. Finally, it provides the necessary basis for the civil law with which it is connected, whether by a reflection that draws conclusions from its Principles, or by additions of a positive and juridical nature.

The term "merit" refers in general to the recompense owed by a community or a society for the action of one of its members, experienced either as beneficial or harmful, deserving reward or punishment. Merit is relative to the virtue of justice, in conformity with the Principle of equality which governs it.

The Church, the "pillar and bulwark of the truth," "has received this solemn command of Christ from the apostles to announce the saving truth." 74 "To the Church belongs the right always and everywhere to announce moral Principles, including those pertaining to the social order, and to make judgments on any human affairs to the extent that they are required by the fundamental rights of the human perSon or the salvation of souls." 75

Non-combatants, wounded soldiers, and priSoners must be respected and treated humanely. Actions deliberately contrary to the law of nations and to its universal Principles are crimes, as are the orders that command such actions. Blind obedience does not suffice to excuse those who carry them out. Thus the extermination of a people, nation, or ethnic minority must be condemned as a mortal sin. One is morally bound to resist orders that command genocide.

It is an illusion to claim moral neutrality in scientific research and its applications. On the other hand, guiding Principles cannot be inferred from simple technical efficiency, or from the usefulness accruing to some at the expense of others or, even worse, from prevailing ideologies. Science and technology by their very nature require unconditional respect for fundamental moral criteria. They must be at the service of the human perSon, of his inalienable rights, of his true and integral good, in conformity with the plan and the will of God.

Love toward oneself remains a fundamental Principle of morality. Therefore it is legitimate to insist on respect for one's own right to life. Someone who defends his life is not guilty of murder even if he is forced to deal his aggressor a lethal blow:

The family must be helped and defended by appropriate social measures. Where families cannot fulfill their responsibilities, other social bodies have the duty of helping them and of supporting the institution of the family. Following the Principle of subsidiarity, larger communities should take care not to usurp the family's prerogatives or interfere in its life.

The minister should ask nothing for the administration of the sacraments beyond the offerings defined by the competent authority, always being careful that the needy are not deprived of the help of the sacraments because of their poverty." 56 The competent authority determines these "offerings" in accordance with the Principle that the Christian people ought to contribute to the support of the Church's ministers. "The laborer deserves his food." 57

The right to religious liberty can of itself be neither unlimited nor limited only by a "public order" conceived in a positivist or naturalist manner. 39 The "due limits" which are inherent in it must be determined for each social situation by political prudence, according to the requirements of the common good, and ratified by the civil authority in accordance with "legal Principles which are in conformity with the objective moral order." 40

Our moral life has its source in faith in God who reveals his love to us. St. Paul speaks of the "obedience of faith" 9 as our first obligation. He shows that "ignorance of God" is the Principle and explanation of all moral deviations. 10 Our duty toward God is to believe in him and to bear witness to him.

The Magisterium of the Pastors of the Church in moral matters is ordinarily exercised in catechesis and preaching, with the help of the works of theologians and spiritual authors. Thus from generation to generation, under the aegis and vigilance of the pastors, the "deposit" of Christian moral teaching has been handed on, a deposit composed of a characteristic body of rules, commandments, and virtues proceeding from faith in Christ and animated by charity. Alongside the Creed and the Our Father, the basis for this catechesis has traditionally been the Decalogue which sets out the Principles of moral life valid for all men.

A society is a group of perSons bound together organically by a Principle of unity that goes beyond each one of them. As an assembly that is at once visible and spiritual, a society endures through time: it gathers up the past and prepares for the future. By means of society, each man is established as an "heir" and receives certain "talents" that enrich his identity and whose fruits he must develop. 3 He rightly owes loyalty to the communities of which he is part and respect to those in authority who have charge of the common good.

Unintentional ignorance can diminish or even remove the imputability of a grave offense. But no one is deemed to be ignorant of the Principles of the moral law, which are written in the conscience of every man. the promptings of feelings and passions can also diminish the voluntary and free character of the offense, as can external pressures or pathological disorders. Sin committed through malice, by deliberate choice of evil, is the gravest.

God is the sovereign master of his plan. But to carry it out he also makes use of his creatures' co-operation. This use is not a sign of weakness, but rather a token of almighty God's greatness and goodness. For God grants his creatures not only their existence, but also the dignity of acting on their own, of being causes and Principles for each other, and thus of co-operating in the accomplishment of his plan.

Since the beginning the Christian faith has been challenged by responses to the question of origins that differ from its own. Ancient religions and cultures produced many myths concerning origins. Some philosophers have said that everything is God, that the world is God, or that the development of the world is the development of God (Pantheism). Others have said that the world is a necessary emanation arising from God and returning to him. Still others have affirmed the existence of two eternal Principles, Good and Evil, Light and Darkness, locked, in permanent conflict (Dualism, Manichaeism). According to some of these conceptions, the world (at least the physical world) is evil, the product of a fall, and is thus to be rejected or left behind (Gnosticism). Some admit that the world was made by God, but as by a watch-maker who, once he has made a watch, abandons it to itself (Deism). Finally, others reject any transcendent origin for the world, but see it as merely the interplay of matter that has always existed (Materialism). All these attempts bear witness to the permanence and universality of the question of origins. This inquiry is distinctively human.

The whole divine economy is the common work of the three divine perSons. For as the Trinity has only one and the same natures so too does it have only one and the same operation: "The Father, the Son and the Holy Spirit are not three Principles of creation but one principle." 97 However, each divine person performs the common work according to his unique personal property. Thus the Church confesses, following the New Testament, "one God and Father from whom all things are, and one Lord Jesus Christ, through whom all things are, and one Holy Spirit in whom all things are". 98 It is above all the divine missions of the Son's Incarnation and the gift of the Holy Spirit that show forth the properties of the divine persons.

At the outset the Eastern tradition expresses the Father's character as first origin of the Spirit. By confessing the Spirit as he "who proceeds from the Father", it affirms that he comes from the Father through the Son. 77 The Western tradition expresses first the consubstantial communion between Father and Son, by saying that the Spirit proceeds from the Father and the Son (filioque). It says this, "legitimately and with good reason", 78 for the eternal order of the divine persons in their consubstantial communion implies that the Father, as "the Principle without principle", 79 is the first origin of the Spirit, but also that as Father of the only Son, he is, with the Son, the single principle from which the Holy Spirit proceeds. 80 This legitimate complementarity, provided it does not become rigid, does not affect the identity of faith in the reality of the same mystery confessed.

The Latin tradition of the Creed confesses that the Spirit "proceeds from the Father and the Son (filioque)". the Council of Florence in 1438 explains: "The Holy Spirit is eternally from Father and Son; He has his nature and subsistence at once (simul) from the Father and the Son. He proceeds eternally from both as from one Principle and through one spiration... And, since the Father has through generation given to the only-begotten Son everything that belongs to the Father, except being Father, the Son has also eternally from the Father, from whom he is eternally born, that the Holy Spirit proceeds from the Son." 75

But since Sacred Scripture is inspired, there is another and no less important Principle of correct interpretation, without which Scripture would remain a dead letter. "Sacred Scripture must be read and interpreted in the light of the same Spirit by whom it was written." 77

After the unity of the human race was shattered by sin God at once sought to save humanity part by part. the covenant with Noah after the flood gives expression to the Principle of the divine economy toward the "nations", in other words, towards men grouped "in their lands, each with (its) own language, by their families, in their nations". 9

"Our holy mother, the Church, holds and teaches that God, the first Principle and last end of all things, can be known with certainty from the created world by the natural light of human reaSon." 11 Without this capacity, man would not be able to welcome God's revelation. Man has this capacity because he is created "in the image of God". 12

The world, and man, attest that they contain within themselves neither their first Principle nor their final end, but rather that they participate in Being itself, which alone is without origin or end. Thus, in different ways, man can come to know that there exists a reality which is the first cause and final end of all things, a reality "that everyone calls God". 10

In Sacred Scripture the term "soul" often refers to human life or the entire human perSon. 230 But "soul" also refers to the innermost aspect of man, that which is of greatest value in him, 231 that by which he is most especially in God's image: "soul" signifies the spiritual Principle in man.

Mortal sin, by attacking the vital Principle within us - that is, charity - necessitates a new initiative of God's mercy and a conversion of heart which is normally accomplished within the setting of the sacrament of reconciliation:

Prudence is the virtue that disposes practical reaSon to discern our true good in every circumstance and to choose the right means of achieving it; "the prudent man looks where he is going." 65 "Keep sane and sober for your prayers." 66 Prudence is "right reason in action," writes St. Thomas Aquinas, following Aristotle. 67 It is not to be confused with timidity or fear, nor with duplicity or dissimulation. It is called auriga virtutum (the charioteer of the virtues); it guides the other virtues by setting rule and measure. It is prudence that immediately guides the judgment of conscience. the prudent man determines and directs his conduct in accordance with this judgment. With the help of this virtue we apply moral Principles to particular cases without error and overcome doubts about the good to achieve and the evil to avoid.

The dignity of the human perSon implies and requires uprightness of moral conscience. Conscience includes the perception of the Principles of morality (synderesis); their application in the given circumstances by practical discernment of reasons and goods; and finally judgment about concrete acts yet to be performed or already performed. the truth about the moral good, stated in the law of reason, is recognized practically and concretely by the prudent judgment of conscience. We call that man prudent who chooses in conformity with this judgment.

The Church is one because of her source: "the highest exemplar and source of this mystery is the unity, in the Trinity of PerSons, of one God, the Father and the Son in the Holy Spirit." 259 The Church is one because of her founder: for "the Word made flesh, the prince of peace, reconciled all men to God by the cross, . . . restoring the unity of all in one people and one body." 260 The Church is one because of her "soul": "It is the Holy Spirit, dwelling in those who believe and pervading and ruling over the entire Church, who brings about that wonderful communion of the faithful and joins them together so intimately in Christ that he is the Principle of the Church's unity." 261 Unity is of the essence of the Church:

The Holy Spirit is "the Principle of every vital and truly saving action in each part of the Body." 247 He works in many ways to build up the whole Body in charity: 248 by God's Word "which is able to build you up"; 249 by Baptism, through which he forms Christ's Body; 250 by the sacraments, which give growth and healing to Christ's members; by "the grace of the apostles, which holds first place among his gifts"; 251 by the virtues, which make us act according to what is good; finally, by the many special graces (called "charisms"), by which he makes the faithful "fit and ready to undertake various tasks and offices for the renewal and building up of the Church." 252

"What the soul is to the human body, the Holy Spirit is to the Body of Christ, which is the Church." 243 "To this Spirit of Christ, as an invisible Principle, is to be ascribed the fact that all the parts of the body are joined one with the other and with their exalted head; for the whole Spirit of Christ is in the head, the whole Spirit is in the body, and the whole Spirit is in each of the members." 244 The Holy Spirit makes the Church "the temple of the living God": 245

Christ "is the head of the body, the Church." 225 He is the Principle of creation and redemption. Raised to the Father's glory, "in everything he (is) preeminent," 226 especially in the Church, through whom he extends his reign over all things.

Finally, Christ's Resurrection - and the risen Christ himself is the Principle and source of our future resurrection: "Christ has been raised from the dead, the first fruits of those who have fallen asleep. . . For as in Adam all die, so also in Christ shall all be made alive." 528 The risen Christ lives in the hearts of his faithful while they await that fulfilment. In Christ, Christians "have tasted. . . the powers of the age to come" 529 and their lives are swept up by Christ into the heart of divine life, so that they may "live no longer for themselves but for him who for their sake died and was raised." 530

This Principle of integral observance of the Law not only in letter but in spirit was dear to the Pharisees. By giving Israel this principle they had led many Jews of Jesus' time to an extreme religious zeal. 334 This zeal, were it not to lapse into "hypocritical" casuistry, 335 could only prepare the People for the unprecedented intervention of God through the perfect fulfilment of the Law by the only Righteous One in place of all sinners. 336

To conclude this Prologue, it is fitting to recall this pastoral Principle stated by the Roman Catechism: