I do object to the assumption that anything that might be outside of nature is ruled out of the conversation. That's an impoverished view of the kinds of questions we humans can ask, such as "Why am I here?", "What happens after we die?", "Is there a God?" If you refuse to acknowledge their appropriateness, you end up with a zero probability of God after examining the natural world because it doesn't convince you on a proof basis.

Presumably there is indeed no purpose in the ultimate fate of the cosmos, but do any of us really tie our life's hopes to the ultimate fate of the cosmos anyway? Of course we don't; not if we are sane. Our lives are ruled by all sorts of closer, warmer, human ambitions and perceptions.

Though the details differ across the world, no known culture lacks some version of the time-consuming, wealth consuming, hostility provoking rituals, the anti-factual, counter-productive fantasies of religion.

Science replaces private prejudice with public, verifiable evidence.

Design cannot precede evolution and therefore cannot underlie the universe.

In our prehistoric past, we would have lived in extended families, surrounded by kin whose interests we might have wanted to promote because they shared our genes. Now we live in big cities. We are not among kin nor people who will ever reciprocate our good deeds. It doesn't matter. Just as people engaged in sex with contraception are not aware of being motivated by a drive to have babies, it doesn't cross our mind that the reason for do-gooding is based in the fact that our primitive ancestors lived in small groups.

The feeling of awed wonder that science can give us is one of the highest experiences of which the human psyche is capable. It is a deep aesthetic passion to rank with the finest that music and poetry can deliver. It is truly one of the things that make life worth living and it does so, if anything, more effectively if it convinces us that the time we have for living is quite finite.