What are some of the main themes of existentialism?

Question:

What are some of the main themes of existentialism?

Best Answer - Chosen by Asker: The first "theme" or tenet is the importance of personal responsibility.
The other main tenets are isolation, death, and meaning.
These lead to problems with freedom, boredom, dread, and alienation versus belonging.

In other words, the individual is between being and nothingness, and so being, s/he must CHOOSE and be RESPONSIBLE to MEANING.

That choice will be put off by dread or boredom or "existential nausea," but in putting it off those very aspects increase in the person. A decision must be made, and it must be made despite isolation, alienation and impending death. It does not matter how "absurd" the decision or CHOICE may appear to others (as in Sisyphus' eternal pushing of the rock up the hill, only to find it back at his feet). The decision must be made, and one must give it MEANING, and be RESPONSIBLE to it in order to find any reason, at all for living or dying. There is NO EXIT.

Tenets in sum:
Choice
Meaning
Responsibility
Death
(within those come freedom, nausea, dread, fear, isolation, loneliness, and, of course, the necessity to deal with absurdity.)

Having said that, Existentialists vary greatly among themselves. Camus, for example, despite opinion to the contrary, did NOT think of himself as an Existentialist.

Sartre's atheistic views of Existentialism differ greatly from the very Christian views of the Existentialists, Soren Kierkegaard (father of Existentialism) and the Jesuit, Jacques Maritain.

It is not true to believe that the philosophy of absurdity and existentialism are one. They are not (although one tends to derive from the other).