Here are the main points I take away from his account (which is mainly based on studies of hunter-gather cultures that survived into modern times):
The paleolithics lived in tiny groups in which they dealt with others on a face-to-face basis. In such a world, individual human life is precious. Even the life of a malefactor has value. These cultures try to avoid imposing the death penalty, and even exile is viewed with distaste.
Throughout the paleolithic and well into the neolithic, war as we think of it was rare to nonexistent. (I would say there is a big ethical difference, which is not just a matter of degree, between raiding and feuding on the one hand and war on the other.)
Paleo cultures were egalitarian. Decisions about the group were typically made by the elders, who could be men or women. Decision-making authority was thus based on age, which indicates possession of natural values such as experience and relative wisdom.
Paleo social organization was often either matriarcal or matrilineal or both. Well into the neolithic, the principal deity was often female.At the heart of the moral revolution of the neolithic is a sort of moral anesthesia, caused by a number of factors, not the least of which is the organization of activity under that the Nazis called the Führerprinzip. It is an occasional convenient blindness (which could never become constant lest culture itself should collapse) to the inviolability of the individual.
With the neolithic came a population explosion and people became more expendable. [They lose what Jeffers called "the value of rarity."]
At the same time, decision-making authority is based more and more on brute force (the strong man) and inheritance (ie., on convention) instead of natural merit. Broad, long-range social organization begins.
Meanwhile, stores of neolithic food surpluses become thief-magnets. People use the new, coercive forms of organization to steal the food of others. Proto-states arise and, with them, organized warfare. Large numbers of morally innocent human beings are coldly slaughtered.
Among the goods stolen in wars are human beings. Slavery is born.
Life-long monogamy is the paleo form of marriage. In the neo world, polygamy arises: mainly polygyny, which priviledges men. It also increases class inequality, as it draws potential mates away from lower-caste men. If it spreads far enough, many lower caste men will not be able to reproduce at all. [I also wonder if it also tends to propagate the thuggish traits that enable one to achieve a position of artificial privilege.]
Beginning in the neolithic, there is a tendency for human wealth, regardless of who produces it, to be channeled to a privileged few. The first taxes are collected.
Because people now live in the same place from generation to generation (no need to follow the mastodon herds) they acquire special holy places (eg., Stonehenge) where they can go and perform the same repetitive rituals in the same place over and over again. Organized religion begins to displace the individualistic spirituality of the paleos. [I would add that this makes possible priestly castes, with coercive power undreamt of by the medicine men of the paleolithic.] Eventually, the religious practice of human sacrifice [the ultimate expression of the subordination of the individual to the group] begins.