I think what you actually mean is human consciousness. If not, let me know and we'll talk about conscience.
Just because all fathers are men doesn't mean all men are fathers. Likewise, just because all life is chemical reactions doesn't mean all chemical reactions are life. The complete consensual definition of life uses several advanced processes as criteria, for example metabolism, growth and reproduction.
Consciousness in the materialistic view goes beyond the chemical, because it's augmented by the bio-electrical. Thoughts literally zap around the brain when they're active. The rest of the time they're stored chemically in the brain cells. The rest of the body also uses small amounts of electricity (there's a reason we need to consume electrolytes), but it's doubly important to the brain.
The nature of the universe does not appear to be to create life wherever possible. Firstly, there are very few types of place in the universe where life is possible, so it's not easy. Secondly, since all known life shares genetic material and is therefore related, it appears that even here on Earth life only emerged once, and never again. I'm not saying we're the only life in the universe, but life seems so rare and unlikely to arise in any given place that the next occurrence of it is probably several galaxies away.
It does seem pointless to create a universe with nobody to experience it. It seems almost as pointless to create a universe and put nearly all of it completely out of reach of the observers, so our presence isn't exactly a masterstroke in the efficient use of the cosmos. It's exactly as if we are just here, and we can see what we can see simply because it's close.
Hope that lot is food for thought.
Hello and welcome, Celia. The one-thing-at-a-time approach will be just fine. Amber123 recently did the same thing.
The answer to this specific question is rooted in human evolution. At every stage in our development as a species there has been fierce competition for the resources necessary to survive. The survivors all the way along have been not just the strongest or the smartest, but those with the greatest will to live.
We didn't always have religion to drive us, you know. Before our ancestors even had the intelligence to conceive of gods or ponder the meaning of life, if they lacked a strong will to survive they would not have survived and we wouldn't be here. Those who were content not to survive or procreate were quickly scooped out of the gene pool by the dangers of the harsh ancient world. The survivors passed down their determination to us, as instinct.
On a personal intellectual level, I'm an atheist and I want to survive because I don't think I have any other life but this. There is a great deal of joy to be had, and to spread, and I want to make the most of it before I die.