"Ever since language allowed human cultural evolution to impinge upon age-old processes of biological evolution, humankind has been in a position to upset older balances of nature in quite the same fashion as disease upsets the natural balance within a host's body. Time and again, a temporary approach to stabilization of new relationships occurred as natural limits to the ravages of humankind upon other life forms manifested themselves. Yet, sooner or later, and always within a span of time that remained miniscule in comparison with the standards of biological evolution, humanity discovered new techniques allowing fresh exploitation of hitherto inaccessible forms of life."

“Like Christianity, Buddhism explained suffering. In forms that established themselves in China, Buddhism offered the same sort of comfort to bereaved survivors and victims of violence or of disease as Christian faith did in the Roman world. Buddhism of course originated in India, where disease incidence was probably always very high as compared with civilizations based in cooler climates; Christianity, too, took shape in the urban environments of Jerusalem, Antioch, and Alexandria where the incidence of infectious disease was certainly very high as compared to conditions in cooler and less crowded places. From their inception, therefore, both faiths had to deal with sudden death by disease as one of the conspicuous facts of human life. Consequently, it is not altogether surprising that both religions taught that death was a release from pain, and a blessed avenue of entry upon a delightful afterlife where loved ones would be reunited, and earthly injustices and pains amply compensated for.”

“Ingenuity, knowledge, and organization alter but cannot cancel humanity's vulnerability to invasion by parasitic forms of life. Infectious disease which antedated the emergence of humankind will last as long as humanity itself, and will surely remain, as it has been hitherto, one of the fundamental parameters and determinants of human history.”

“Religious history also offers another striking parallel between Rome and China. The Buddhist faith began to penetrate the Han empire in the first century A.D., and soon won converts in high places. Its period of official dominance in court circles extended from the third to the ninth centuries A.D. This obviously parallels the successes that came to Christianity in the Roman empire during the same period.”

“Details of early domestications remain unclear. One must assume a process of mutual accommodation between humanity and various domesticable species. This involved rapid and sometimes far-reaching change in the biological character of domesticated plants and animals as a result of both accidental and deliberate selection for particular traits. Conversely, one can assume that a radical, if rarely deliberate, selection among human beings occurred as well. Individuals who refused to submit to laborious routines of farming, for instance, must often have failed to survive, and those who could not or would not save seed for next year's planting, and instead ate all they had, were quickly eliminated from communities that become dependent upon annual crops.”

“I departed from parental paths significantly and abruptly one Sunday morning when, sitting in the family pew of the Hyde Park United Church and idly twisting a loose button on the cushion beside me, I said to myself, "I do not believe in God." Some months previously... when our minister fell back on St. Anselm's ontological argument to prove the existence of God, he entirely failed to convince me. Quite the contrary, the argument struck me as an abuse of language. Though I duly submitted to the ritual of confirmation... Horton's unconvincing argument had sown doubt in my mind; and for that reason I can assign, on that morning, listening to his more emotional, hortatory rhetoric... the balance tipped, committing me to a secret, personal rejection of the Christian piety my parents held dear.”

“The diffusion of alchemy westward, like the movement of astrology eastward, became significant only in the centuries after 200 A.D. The conservatism of learning was such that, even when commercial intercourse had made intellectual contacts possible, little serious interchange took place until severe social stress had disturbed the even tenor of the times in China, India, and Europe. Technology was a little, but only a little, less conservative.”