There are at least two senses in which the term philosophy is used, a formal and an informal sense. In the formal sense philosophy is an academic study of the fields metaphysics, ethics, epistemology, logic, and social philosophy. Philosophy of life is philosophy in the informal sense, as a way of life whose focus is resolving the existential questions about the human condition.

The human situation appears to be a struggle between what is (existence) and what ought (essence) to be.

• Normative situation -- Alternatives, Choice, Freedom, Values, Standards, Ideals, Obligation, Responsibility

• Existential predicament -- Finitude, Alienation, Anxiety, Guilt, Ambivalence, Thrownness

There are at least three prevailing theories on how to respond to the Existential question.

• Regression, pre-human existence
• Nihilism, denial of meaning

• Humanism
• Christianity
• Zen

• Eastern mysticism
• Essentialism

There are two basic forms of Existentialism:

Religious existentialism is best exemplified by St. Augustinem Blaise Pascal, Paul Tillich, and the philosophy of Søren Kierkegaard. Religious existentialism holds that there are two levels of reality, essence, which is the ground of Being and existence. Religion is the ultimate concern, in this view.

Atheistic existentialism is best exemplified by Friedrick Nietzsche, Martin Heidegger, and Jean-Paul Sartre.

Atheistic existentialism holds that there is one level of reality, existence. In this view, each person constructs his own unique and temporary essence.

• Human situation
• Essence
• Existence
• Meaning of life
• Absurdity
• Existential crisis