This is a definition from the Supreme Court case Murray v. Curlett, one of the cases in which the Supreme Court in 1963 struck down both Bible reading and the Lord's Prayer in public schools as a violation of the 1st Amendment.
An Atheist loves himself and his fellow man instead of a god.
An Atheist accepts that heaven is something for which we should work now, here on earth, for all men together to enjoy.
An Atheist accepts that he can get no help through prayer, but that he must find in himself the inner conviction and strength to meet life, to grapple with it, to subdue it and to enjoy it.
An Atheist accepts that only in a knowledge of himself and a knowledge of his fellow man can he find the understanding that will help to reach a life of fulfillment.