Atheism is too simple. And I will tell you another view that is also too simple. It is the view I call Christianity-and-water, the view which simply says there is a good God in Heaven and everything is all right -- leaving out all the difficult and terrible doctrines about sin and hell and the devil, and the redemption. Both these are boys' philosophies.
It is no good asking for a simple religion. After all, real things are not simple. They look simple, but they are not. The table I am sitting at looks simple1: but ask a scientist to tell you what it is really made of--all about the atoms and how the light waves rebound from them and hit my eye and what they do to the optic nerve and what it does to my brain--and, of course, you find that what we call 'seeing a table' lands you in mysteries and complications which you can hardly get to the end of.2
If we are to understand our universe we had better get used to mystery. Indeed, it is that mystery which is the very thing pointing toward God and things beyond this or other universes.
1 For more on how "unsimple" things really are see Space.
2 C.S. Lewis, Mere Christianity (Macmillan, 1952), Book 2, Chapter 2, "The Invasion"