ROTTEN BASTARD!
That's me at times I'm afraid folks. As an atheist, and a Humanist, I have a relationship with religious people that varies in proportion to their tendency to be fundamentalist, or not.

In discussion with one person who has a very personal relationship with his vision of God, denies being religious in any organised sense and says that Christianity is just a man made story, he was referencing everything to God.

Then he mentioned, "2001: A Space Odyssey" as containing an illustration of a point he wanted to make. Being a science fiction fan and with a tendency towards an interest in philosophy my memory prickled on this subject. Arthur C. Clarke, the author of the story, is an atheist and a supporter of Humanism, hmmm, let's look further ...

The musical introduction for the film is the introduction from Richard Strauss' "Also Sprach Zarathustra", one of those pieces of music that should be listened to with enough volume to make your belly wobble on the kettle drum beats!

This piece of music was inspired by Friederich Nietzche's book of the same title. This was a famous, perhaps infamous, book that declared that God is dead. Thus one might interpret the "theme" of the film as being that God is dead, but the alien entity that enabled the apes to become men is still very much alive! Or, perhaps, God and the alien are one and the same.

My discussion mate took this news rather philosophically I have to admit, but he did not really want to accept it and asked for reiterations more than once.

Refs:

Strauss:
http://en.wikipedia.org/wiki/Also_sprach_Zarathustra_(Richard_Strauss)

Nietzche:
http://en.wikipedia.org/wiki/Also_sprach_Zarathustra

2001:
http://en.wikipedia.org/wiki/2001:_A_Space_Odyssey