Animals with a spirit and God to guide us. We instinctively know this. Some just deny this spiritual instinct as an excuse to be evil. I place courage and character above all else. I care little for what you have, but, I measure people on how they use their resources (if in abundance), how you treat others.
You "instinctively know this", but you can't prove it, and it doesn't really make sense.
1) because humans end up doing the same things all the time, just like animals. We're born with genes, we're born with INSTINCTS, as you said, and these instincts are usually what drive us, rather than us thinking for ourselves.
2) because if you look at explosions, you can figure out what happened at the explosion, by seeing what is left over. The MA flight that got shot down over the Ukraine, they could tell what weapon shot it down, by examining the fragments.
The Big Bang (assuming it existed) would have been the same. If we took EVERYTHING in the universe (impossible, but hey) we could work back and see how it happened.
3) Figure out why you do things.
Nurture v. nature.
Nurture is what people did to you. A teacher said this, a doctor said that, a friend said the other. They all did this based on their own nature v. nurture and the people who nurtured them were nurtured by people who were nurtured and back and back and back until time immemorial.
Nature are your genes, clearly they go back to time immemorial too. You parents gave you genes which were given them.
The reality is EVERYTHING IS INEVITABLE. One thing that is inevitable is that humans have a survival instinct and part of that is to think that everything isn't inevitable and that we have control of ourselves.
Another seems to be the creation of fantasy worlds, to hide from reality, the more complex we become, the more we need fantasy worlds. We also feel the need to be in control. Creating a God in which we can dance, sacrifice, pray to, in order for us to have an impact on the weather, on other people and so on, it's just a need to be in control.