Some of Isaac Asimov’s thoughts on religion and spirituality (via Brain Pickings):
I have never, not for one moment, been tempted toward religion of any kind. The fact is that I feel no spiritual void. I have my philosophy of life, which does not include any aspect of the supernatural and which I find totally satisfying. I am, in short, a rationalist and believe only that which reason tells me is so.
And his thoughts on being a humanist (he was for a time president of the American Humanist Association):
I’ve never been particularly careful about what label I placed on my beliefs. I believe in the scientific method and the rule of reason as a way of understanding the natural Universe. I don’t believe in the existence of entities that cannot be reached by such a method and such a rule and that are therefore “supernatural.” I certainly don’t believe in the mythologies of our society, in Heaven and Hell, in God and angels, in Satan and demons. I’ve thought of myself as an “atheist,” but that simply described what I didn’t believe in, not what I did.
Gradually, though, I became aware that there was a movement called “humanism,” which used that name because, to put it most simply, Humanists believe that human beings produced the progressive advance of human society and also the ills that plague it. They believe that if the ills are to be alleviated, it is humanity that will have to do the job. They disbelieve in the influence of the supernatural on either the good or the bad of society, on either its ills or the alleviation of those ills.