If you go back 50,000 years to the Paleolithic era, to the early days of Homo sapiens, what we find is that the world was filled with danger, all of these forces working very, very hard to kill us.
如果你往回倒推 5 万年， 回到旧石器时代， 到智人生活的早期， 我们会发现 世界充满了危险， 所有的力量都在努力要杀死我们。