Just because someone is an atheist doesn't mean that they don't beleive in things greater than themselves.
I beleve, or have faith in the followion things, democracy (though I must admit this is a trying time for my faith), Science, the power of rational debate, certian ethical theories, and even the various communities that I am part of.
Do these qualify as things that are greater than myself? They are not greater than mankind perhaps but they are greater than any one human.
Perhaps if you explained what you meant by this phrase we could discuss it better.