Existentialism: Existentialism represents an attempt to refocus consideration of moral decisions from the issue confronted to the "actor" confronting the issue. The focus of Existentialism is upon the role of "human choice" which evidences the Existentialist confidence in human freedom. The paradox of Existentialism lies in the belief that in our choices we restrict our destiny and ultimately determine who we will be and what we will be like. Advocates of existential ethics include Jean Paul Sartre, Albert Camus, and Martin Heidegger.
Hume and the Naturalistic Fallacy: No "is" implies an "ought." No factual claims, such as those about whether actions produce pleasure, can be the basis for statements about what we are obligated to do. This is designated as "the naturalistic fallacy" since it takes something that is part of nature and tries to make a metaethical claim or one that transcends nature. The Naturalistic Fallacy is associated with the work of David Hume.
G. E. Moore: Since the good cannot be defined in terms of any natural quality then the attempt to define the good in terms of other facts must result in a fallacy. The alternative is that good is simply a quality like yellow or blue. You either know it or you don't.
Logical Positivism: Moral statements are neither analytic or true b definition nor are they synthetic, true by observation. They merely express a feeling or a command. They are not true or false except insofar as they tell us about the feelings of another. A. J. Ayer and Ludwig Wittgenstein are advocates of Logical Positivism, though the later Wittgenstein reflects somewhat of a departure from the movement.
Cultural Relativism: Moral values are relative to one’s culture. There are no universally held values.
Ethical relativism: No one set of morality or values ought to be applied to all
Nietzsche and the Will to Power: For Nietzsche, ethics is essentially an expression of the impulse to create value, the will to life and the will to power. The creation of value is good because it promotes advancement beyond the human.
