"there needs to be some force that keeps humanity from tearing itself apart" . 1:22:40.

From the biology point of view we have part of he brain that was specifically design to exist as we are. Cerebral cortex wasn't it? They say that the basis of this is the evolutionary adaptation when sharing food with none relatives gives advantage over other species that's why there things like love, empathy and all that considered socially acceptable exist. The part is basically about "living in a society without killing one another"

There is the reptilian brain part which is concerned with sex food and evading danger. Also the memory thingy that remembers what simple weapons might do and also nuke's when we talk about international conflicts.

Revenge and killing isn't that bad when it's social standard like it is (was) in some tribes or primitive societies. According to Steven Pinker's "the Better Angels of our nature" humans enjoy killing and torturing each other. It might be looked at as having biological advantages of eliminating opponents or gaining food source for free. Also the brain is too sneaky to explain itself which is usually expressed as different biases, there's that confirmation bias , fact fabrication's... Basically our brain has self- defense mechanisms against "Nietzsches" making them feel good about particular ideas so that they would stop thinking too hard eventually. Saves energy too...

I think people lives are just about experiencing hormones. So even a thought can cause a hormonal discharge to make you feel good or bad about yourself. Hormones or substances that directly influence reward system have been available for some thousands of years so basically our path is limited at one side to what activity we find to get most of our hormonal system and at the other side by physical reality which so far is that we are all playing 0 sum game cos the universe will end in thermal death. Should we worry about it?