section_path: Philosophy/Ethics
section_name: Ethics
paragraph_text: Ethics
  
  Thomas was aware that the Albigensians and the Waldensians challenged moral precepts concerning marriage and ownership of private property and that challenges could ultimately be resolved only by logical arguments based on self-evident norms. He accordingly argued, in the Summa Theologiae, that just as the first principle of demonstration is the self-evident principle of noncontradiction ("the same thing cannot be affirmed and denied at the same time"), the first principle of action is the self-evident Bonum precept ("good is to be done and pursued and evil avoided").
  
  This natural law precept prescribes doing and pursuing what reason knows is good while avoiding evil. Reason knows what is objectively good because good is naturally beneficial and evil is the contrary. To explain goods that are naturally self-evident, Thomas divides them into three categories: substantial goods of self-preservation desired by all; the goods common to both animals and humans, such as procreation and education of offspring; and goods characteristic of rational and intellectual beings, such as living in community and pursuing the truth about God.
  
  To will such natural goods to oneself and to others is to love. Accordingly, Thomas states that the love precept obligating loving God and neighbour are "the first general principles of the natural law, and are self-evident to human reason, either through nature or through faith. Wherefore all the precepts of the decalogue are referred to these, as conclusions to general principles."
  
  To so focus on lovingly willing good is to focus natural law on acting virtuously. In his Summa Theologiae, Thomas wrote:
  
  Virtue denotes a certain perfection of a power. Now a thing's perfection is considered chiefly in regard to its end. But the end of power is act. Wherefore power is said to be perfect, according as it is determinate to its act.
  
  Thomas emphasized that " Synderesis is said to be the law of our mind, because it is a habit containing the precepts of the natural law, which are the first principles of human actions."
  
  According to Thomas "... all acts of virtue are prescribed by the natural law: since each one's reason naturally dictates to him to act virtuously. But if we speak of virtuous acts, considered in themselves, i.e., in their proper species, thus not all virtuous acts are prescribed by the natural law: for many things are done virtuously, to which nature does not incline at first; but that, through the inquiry of reason, have been found by men to be conducive to well living." Therefore, we must determine if we are speaking of virtuous acts as under the aspect of virtuous or as an act in its species.
  
  Thomas defined the four cardinal virtues as prudence, temperance, justice, and fortitude. The cardinal virtues are natural and revealed in nature, and they are binding on everyone. There are, however, three theological virtues: faith, hope, and charity. Thomas also describes the virtues as imperfect (incomplete) and perfect (complete) virtues. A perfect virtue is any virtue with charity, charity completes a cardinal virtue. A non-Christian can display courage, but it would be courage with temperance. A Christian would display courage with charity. These are somewhat supernatural and are distinct from other virtues in their object, namely, God:
  
  Now the object of the theological virtues is God Himself, Who is the last end of all, as surpassing the knowledge of our reason. On the other hand, the object of the intellectual and moral virtues is something comprehensible to human reason. Therefore the theological virtues are specifically distinct from the moral and intellectual virtues.
  
  Thomas Aquinas wrote " is a sin against God, just as all mortal sins, in as much as man condemns things eternal for the sake of temporal things."
  
  Furthermore, in his Treatise on Law, Thomas distinguished four kinds of law: eternal, natural, human, and divine. Eternal law is the decree of God that governs all creation: "That Law which is the Supreme Reason cannot be understood to be otherwise than unchangeable and eternal." Natural law is the human "participation" in the eternal law and is discovered by reason. Natural law is based on " first principles ":
  
  ... this is the first precept of the law, that good is to be done and promoted, and evil is to be avoided. All other precepts of the natural law are based on this...
  
  Whether the natural law contains several precepts, or one only is explained by Thomas, "All the inclinations of any parts whatsoever of human nature, e.g., of the concupiscible and irascible parts, in so far as they are ruled by reason, belong to the natural law, and are reduced to one first precept, as stated above: so that the precepts of the natural law are many in themselves, but are based on one common foundation."
  
  The desires to live and to procreate are counted by Thomas among those basic (natural) human values on which all human values are based. According to Thomas, all human tendencies are geared towards real human goods. In this case, the human nature in question is marriage, the total gift of oneself to another that ensures a family for children and a future for mankind. He defined the dual inclination of the action of love: "towards the good which a man wishes to someone (to himself or to another) and towards that to which he wishes some good".
  
  Concerning Human Law, Thomas concludes, "... that just as, in the speculative reason, from naturally known indemonstrable principles, we draw the conclusions of the various sciences, the knowledge of which is not imparted to us by nature, but acquired by the efforts of reason, so to it is from the precepts of the natural law, as from general and indemonstrable principles, that human reason needs to proceed to the more particular determination of certain matters. These particular determinations, devised by human reason, are called human laws, provided the other essential conditions of law be observed..." Human law is positive law: the natural law applied by governments to societies.
  
  Natural and human law is not adequate alone. The need for human behaviour to be directed made it necessary to have Divine law. Divine law is the specially revealed law in the scriptures. Thomas quotes, "The Apostle says (Hebrews 7.12): The priesthood being translated, it is necessary that a translation also be made of the law. But the priesthood is twofold, as stated in the same passage, viz, the levitical priesthood, and the priesthood of Christ. Therefore, the Divine law is twofold, namely, the Old Law and the New Law."
  
  Thomas also greatly influenced Catholic understandings of mortal and venial sins.
  
  Thomas Aquinas refers to animals as dumb and that the natural order has declared animals for man's use. Thomas denied that human beings have any duty of charity to animals because they are not persons. Otherwise, it would be unlawful to kill them for food. But humans should still be charitable to them, for "cruel habits might carry over into our treatment of human beings."
  
  Thomas contributed to economic thought as an aspect of ethics and justice. He dealt with the concept of a just price, normally its market price or a regulated price sufficient to cover seller costs of production. He argued it was immoral for sellers to raise their prices simply because buyers were in pressing need of a product.