It's commonly assumed that the emergence of language was a key element of the great leap. We of course know very little about the sociopolitical conditions that existed at the time, but there's no scenario i can think of that suggests how a sudden change in these conditions could have led to the emergence of language.
Thus we arrive at the singular conclusion that of all the information passed by our cultural assets it is precisely the elements which might be of the greatest importance to us and which have the task of solving the riddles of the universe and of reconciling us to the sufferings of life -- it is precisely those elements that are the least well authenticated of any.
In the visible world, the milky way is a tiny fragment; within this fragment, the solar system is an infinitesimal speck, and of this speck our planet is a microscopic dot. On this dot, tiny lumps of impure carbon and water, of complicated structure, with somewhat unusual physical and chemical properties, crawl about for a few years, until they are dissolved again into the elements of which they are compounded.
We ought not to listen to those who exhort us, because we are human, to think of human things....We ought rather to take on immortality as much as possible, and do all that we can to live in accordance with the highest element within us; for even if its bulk is small, in its power and value it far exceeds everything.