The atheist definition of God differs quite significantly from that of the Veda's. Their definition is that God must have evolved to become extremely complex, like one of Darwin's organisms evolving over eons of time. On the other hand, the Veda's notion is that God exists outside of time and space and exists within and as all things.
Here's an excerpt from the Upanishads:
"That which makes the tongue speak but which cannot be spoken by the tongue--that alone is God, not what people worship. That which makes the mind think but which cannot be thought by the mind--that alone is God, not what people worship.
That which makes the eye see but which cannot be seen by the eye--that alone is God, not what people worship.
If you think that you know God, you know very little, all that you can know are ideas and images of God." -- The Upanishads