Online Guide to Ethics and Moral Philosophy


Robert Cavalier

Philosophy Department
Carnegie Mellon

Part I History of Ethics

Preface: The Life of Socrates
Section 1: Greek Moral Philosophy
Section 2: Hellenistic and Roman Ethics
Section 3: Early Christian Ethics
Section 4: Modern Moral Philosophy
Section 5: 20th Century Analytic Moral Philosophy

Part II Concepts and Problems

Preface: Meta-ethics, Normative Ethics and Applied Ethics
Section 1: Ethical Relativism
Section 2: Ethical Egoism
Section 3: Utilitarian Theories
Section 4: Deontological Theories
Section 5: Virtue Ethics
Section 6: Liberal Rights and Communitarian Theories
Section 7: Ethics of Care
Section 8: Case-based Moral Reasoning
Section 9: Moral Pluralism

Part III Applied Ethics

Preface: The Field of Applied Ethics
Section 1: The Topic of Euthanasia
Multimedia Module: A Right to Die? The Dax Cowart Case
Section 2: The Topic of Abortion
Multimedia Module: The Issue of Abortion in America
Postscript: Conflict Resolution

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St. Thomas Aquinas

In the 13th Century, Aristotle's works were 'rediscovered' in the West and translated into Latin. These translations of 'The Philosopher' (as Aquinas called him) became an integral part of some of Aquinas' most important writings. (See the Jacques Maritain site at the University of Notre Dame for an overview of Thomas Aquinas' life and work.)


"The ultimate beatitude of man consists in the use of his highest function, which is the operation of his intellect...Hence...the blessed see the essence of God." (Summa Theologica)
  • Translates Aristotle into the Christian Worldview
  • Adds the 'spiritual virtues' of Faith, Love, and Hope
  • Distinguishes between 'Eternal Law,' 'Natural Law,' 'Human Law' and 'Divine Law'
  • Natural Law prescribes the fundamental precepts of morality and is grasped through reason and conscience
In the works of Aquinas, Natural Law Philosophy receives one of its highest expressions. It is a 'law' situated within God's Eternal Law in that "the whole community of the universe is governed by Divine Reason. Wherefore the very Idea of the government of things in God the Ruler of the universe, has the nature of a law. And since the Divine Reason's conception of things is not subject to time but is eternal...it is that therefore this kind of law must be called eternal."

That part of Eternal Law that pertains to the behavior of human beings is the proper domain of Natural Law. Vernon Bourke, quoting from Aquinas, describes it thus:

'Good is to be done and promoted and evil to be avoided' (ST I-II, 94, 2). Since this rule does not specify what is good, it cannot be further analyzed to find more specific moral rules. It is a principle formally governing practical reasoning and in this sense Thomas calls it the first precept of natural law. To determine what are the proximate natural goods for man, Aquinas suggests that reason naturally apprehends as goods those objects that satisfy man's basic inclinations. On the lowest level are those physical goods that all beings incline to, such as self-preservation. Second are biological goods that men tend towards, as do all living things: the procreation and care of offspring, for instance. In the third and highest place he puts those values that satisfy man as a rational being: the knowledge of truth about God and the advantage of living in the society of other humans.
Human Law involves those civil laws that govern communities. These civil laws may indeed vary from town to town as long as they don't violate the precepts of Natural Law.

Finally, Divine Law pertains to God's special plans for humanity and is revealed through, for example, sacred scripture.

Examples of these 'laws' could be (1) the law of gravity as governing the motion of physical objects, (2) prohibition of artificial birth control as violating our natural tendency toward procreation, (3) laws regulating the traffic in a particular city and disobedience with regard to laws that seek to destroy religious faith (through, for example, the banning of Mass), (4) knowledge, through God's Grace, of our supernatural rewards (as revealed in the New Testament).

See Vernon Bourke for a discussion of Aquinas' basic ethical theory. See also excerpts from the Routledge Encyclopedia of Philosophy article on Aquinas. For an example of how Aquinas appropriates Aristotelian moral philosophy, see his discussion of "virtue as a mean" in Summa Theologica.



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Copyright 2002 (first published 1/96)

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