More than half a million years ago, the Neanderthal and human branches of evolution began to split from our common ancestor Homo erectus. Neanderthal, like erectus before, spread out of Africa and across Eurasia. But our ancestors, who acquired fully human structures of brain and body about 200,000 years ago, remained stuck in the savanna grasslands and scrub of eastern then southern Africa. Recent archaeological and DNA analyses suggest that our species may have tottered on the brink of extinction as recently as 70,000 years ago, dwindling to fewer than 2000 souls. Then, in a geological blink of the eye, they became us, traipsing about on the moon and billions strong.
How did it all happen? No real evidence has emerged from science for dramatic change in general anatomy of the human body and brain, or in basic capacities for physical endurance and perception. The key to this astounding and bewildering development may have been a mutation in the computational efficiency of the brain to combine and process concepts—a recursive language of thought and theory of mind—that led to linguistic communication about possible worlds, and to a mushrooming cultural cooperation and creativity within and between groups to better compete against other groups.
From the evanescent beauty of sand paintings among Australian aboriginals and Native Americans to the great and costly ziggurats and pyramids of ancient Mesopotamia, India and Mesoamerica that functioned mainly to stimulate imagination, and from the foragers, herders, cultivators, warriors and innovators of New Guinea, the Amazon, Africa and Europe, a startling multiplicity of social and intellectual forms emerged to govern relations between people and nature.
By the time of Christ, four great neighboring polities spanned Eurasia's middle latitudes along the trading network known as "the Silk Road": the Roman Empire, the Parthian Empire centered in Persia and Mesopotamia, the Kushan Empire of Central Asia and Northern India, and the Han Empire of China and Korea. Along the Silk Road, Eurasia's three universalist moral religions – Judaism, Zoroastrianism and Hinduism –mutated from their respective territorial and tribal origins into the three proselytizing, globalizing religions vying for the allegiance of our species: Christianity, Islam and Buddhism.
The globalizing religions created two new concepts in human thought: individual free choice and collective humanity. People not born into these religions could, in principle, choose to belong (or remain outside), without regard to ethnicity, tribe or territory. The mission of these religions was to extend moral salvation to all peoples, not just to a "Chosen People" that would light the way for others.
Secularized by Europe's Enlightenment, the great quasi religious -isms of modern history —colonialism, socialism, anarchism, fascism, communism, democratic liberalism—harnessed industry and science to continue on a global scale the human imperative of cooperate to compete, or kill massively to save the mass of humanity.
Now, from the multiplicity of human cultural forms, soon there will be likely only one or a few. This is the way of evolution, some scientists say, for in the struggle for life only conquering or isolated forms triumph and survive. But with vigilant intellectual and political effort, hope the humanists among them, in our one interdependent world, democracy, reason, human rights and happiness will flourish.
Yet science also teaches us that much greater interdependence can also lead to much greater vulnerability to cascading and catastrophic collapse from even single, unanticipated events. The two great world wars and global economic crises of the last century could well be indicators of far greater risks to come for humanist hopes.
Calls to "tolerate diversity" and "respect nature" are pale acknowledgements of the problem. Anthropology has virtually disappeared as a science of cultures, with the emphasis now either on personal experience in some slightly exotic place, like contemplating one's own genitals the way others do or don't, or on the cultural dynamics of the mundane, like bench sitters or subway riders. Psychology today considers that comparing, say, American with Chinese college students speaks to the breadth and depth of the human experience, although the apparent differences can be usually erased by a mere change in priming or framing (just suggesting that one might think about something one way rather than another). This tells us little about the true scope and limits of human thought and behavior. And political correctness, which attempts to enforce tolerance, creates bigotry over trivialities.
Science education, too, is deficient: we find that when young Native Americans enter primary schools they score higher than other groups in science-related topics and knowledge of nature, but score lowest when they leave primary school. And our honors biology students show little knowledge of the flora and fauna in front of their eyes, usually no more than a few domesticated and zoo animals, names (but not recognition) of a handful of birds, and "oak, maple, pine and—is Christmas tree a real kind?—I don't know, but I do know a lot about angiosperms and gymnosperms."
As the death of languages and cultures proceeds at a geometric pace, and further efforts at domestication of nature lead to further alienation from it (including establishment of "nature reserves" and efforts to control climate change), we may find our global culture imploding to a point of precariousness not so different from it was 70,000 years ago when the human experience began with a bang.