The Lucretian account of the formation of the cosmos and the evolution of animals, and the Judaeo-Christian account of the divine creation of the world, were recognised as rivals from the early medieval period onwards. Their combat has been long and persistent, but also somewhat hidden from view, which is why Darwin receives too much credit for thinking out the basic idea of evolution by natural selection and too little credit for realising that variation was the key that could solve the problem of the origin of new species. The rivalry was not for a long time manifested in open debate because of the severe criminal penalties attached to blasphemy, a capital crime in earlier periods of Judaism, Christianity and Islam, and because of the ubiquity of censorship in many parts of Europe.
Why were ideas about the origins of life so dangerous? It was thought that if too many people began to take seriously accounts of the natural origins of life, they would cease to believe that they were created by and responsible to the God who had created them. If they stopped believing they were responsible to God, they would stop believing that obedience to God’s commands and their rulers was obligatory and that disobedience would be harshly punished. If they stopped believing that obedience was obligatory, they would become libertines, criminals and revolutionaries.
Today, the fear that motivated execution for heretics and resulted in the banning, confiscation and burning of scientific books takes a different form. It is not fear of revolutionary violence that explains the persistence of Creationism and intelligent design theories. Some Creationists would probably like to overthrow their secular governments by force of arms and replace them with theocracies. The fear is rather that if the Epicurean–Darwinian theory is true and intelligent design false, divinities and religious texts are not sources of moral authority, and eternal life is not the reward for faith. In that case, there is no reason to obey the Ten Commandments or all the moral ordinances of one’s own church. Moral anarchy, by which Creationists usually understand homosexuality, adultery, abortion and divorce, and the breakdown of the family and society, will result.
If the divine-command theory of morality were the only option, and if the inescapability of death actually spoiled our lives, worries about the social and psychological effects of accepting evolutionary theory might be justified. But it was Darwin himself, drawing on a long tradition of secular British moral theory as well as his own observations of birds and mammals, who first argued that certain forms of altruism characterised group living animals, contributing to their survival. Conscience, or a moral sense, would inevitably arise, he declared, in any social animal that had developed intelligence comparable to that of a human being.
More recent research on primates and young children has confirmed that the moral sentiment of empathy and the disposition to help others, along with a preference for fairness, are to some extent prefigured in our evolutionary ancestors and wired into us from birth. These endowments can be strengthened and extended, as Darwin saw, through formal learning, or weakened by experience and indoctrination. And despite having no conception whatsoever of the descent of one species from an entirely different one, the ancient Epicureans had a serviceable theory of natural morality that I’ll explore in Chapter 6. They showed how it was possible to live cheerfully and ethically as a mortal.
3
The spirit … is born with the body, develops with it, and succumbs with it to the stress and strain of age.
Lucretius
Even if you are not tempted by Creationism, you may well wonder how conscious awareness and the power of perception and thought – mind or spirit – could arise from combinations of material particles. In keeping with their sparse ontology of atoms and void, the ancient Epicureans declared the soul – the principle of movement, sensation, experience and thought in living beings – to be composed of a special sort of atom. ‘Soul atoms’, they proposed, were especially small, especially mobile and very lively. They pervaded the limbs of the human body, enabling us to think, feel and move. Unlike the soul of Christian and other theologies, the Epicurean soul was not immortal or an object of special care and concern by contrast with the body.
We feel and know that we are wholly united with our bodies, says Lucretius. ‘The spirit’s interpenetration of the body through veins, flesh, sinews and bones is so complete that even the teeth are given a share in sensation, as is shown by toothache, or the twinge caused by icy water, or the crunching of rough grit concealed in a piece of bread.’ Too much wine has the effect of ‘confounding the spirit within the body’. Now, ‘the limbs become heavy; [the drunkards] reel about with staggering steps; the tongue drawls, the mind is sodden, the eyes swim’. In an epileptic fit ‘the spirit in every part of their frame is so distracted by the violence of the seizure that it surges and foams, just as the waves of the salt sea seethe beneath the furious force of the winds’.
Because body and mind are entirely interwoven, the body cannot live on and experience sensation without its mind, and the mind divorced from the body cannot produce any thought or movement. At the moment of death, the soul particles escape into the surrounding atmosphere without causing any immediate change in the weight or shape of the body. ‘It is like the case of a wine whose bouquet has evaporated, or of a perfume whose exquisite scent has dispersed into the air, or of some object whose flavour has departed.’ The death of the body most certainly means the permanent annihilation of that body’s mind.
The 17th-century philosopher René Descartes, who had no problem with the Epicurean account of the origins of plants and nonhuman animals, famously balked at taking the same view of humans. Where plants and animals are just unconscious material machines, human beings, he argued, are material machines that also possess an incorporeal, immortal soul that endows them with conscious awareness, free will and rationality. Each human soul must have a divine origin. Not only did this claim excuse him from having to try to explain consciousness, free will and rationality in mechanical terms, it enabled the rest of his basically Epicurean ‘corpuscularian’ philosophy to make it past some of, though not all, the censors. (Despite his extensive references to God and the incorporeal soul, his books were viewed with considerable suspicion and for a time appeared on the Index of Prohibited Books of the Catholic Church.)
Descartes’s official theory of the special human soul put him in good and extensive company. The majority of the human race believed in his time, and the majority still believes, that the soul is a something that lives in the body. The soul is thought of as a permanent, indestructible entity that can survive the death of the body. Not only can it survive, it can reattach itself to a new living body – either the resurrected body of the person who died, or one of their descendants, or an animal of another species – where it will continue to see, feel and think to the extent permitted by that body. The Epicurean of today will, however, insist that the soul is not able to detach itself from its original body or attach itself to another unensouled human body. My death, she supposes, will be the end of all my experience and thinking, and it will not be the start of some other being’s experience