On the Nature of Things by Lucretius (c. 50 bce)

Lucretius is the greatest science writer of all time and his long poem On the Nature of Things,^{Reference Stallings1} summarising the speculations of the ancients, still rings remarkably true. Several centuries before, Democritus had coined the term ‘atoms’ to describe the tiny, invisible, indivisible and indestructible building blocks of the universe. These atoms travel interminably in space, occasionally swerving off course, crashing into one another and combining to form ever more complex entities. Life arises from the inanimate and those living organisms survive that are best adapted to their environments. Man is part of the system of nature, not its master, and the universe serves no teleological purpose. It is governed instead by natural laws and the endless workings of blind probabilities. Mind and sensation arise from the material elements built into our physical make-up – there's no soul, no afterlife, no superstition and gods are dead.

Lucretius also offers a practical guide for living well. The goal of life is achieving pleasure and avoiding pain – best done by living modestly; acquiring knowledge; limiting hedonism; quelling excess desire; finding peace of mind; and avoiding the frustrations of political and personal ambition. There's no more reason to fear what happens after your death than to fear what happened before your birth.

Discourses of Epictetus (c. 135 ce)

Epictetus was born a Greek slave, but later gained fame in Rome as a Stoic sage and mentor to Emperor Hadrian. You can get a flavour of Stoic teachings from this sampling of modern renderings of his memorable quotes: ‘There is only one way to happiness and that is to cease worrying about things which are beyond the power of our will’. ‘It's not what happens to you, but how you react to it that matters’. ‘Men are disturbed not by things, but by the view which they take of them’. ‘No man is free who is not master of himself’. ‘First say to yourself what you would be; and then do what you have to do’. ‘Wealth consists not in having great possessions, but in having few wants’. ‘If you want to improve, be content to be thought foolish and stupid’. ‘Only the educated are free’. ‘It is impossible for a man to learn what he thinks he already knows’. ‘We have two ears and one mouth so that we can listen twice as much as we speak’. ‘Any person capable of angering you becomes your master; he can anger you only when you permit yourself to be disturbed by him’. ‘Don't explain your philosophy. Embody it’.

It's no accident that Epictetus² reads like a manual of modern cognitive therapy – Aaron Beck and Albert Ellis both acknowledged having borrowed heavily from Stoic philosophy in their teachings and practice.

The Descent of Man, and Selection in Relation to Sex by Charles Darwin (1871)

Darwin is the towering giant of psychology – the first theorist in its long history to discover the causal roots of human nature. Before Darwin, philosophers offered only descriptions of psychological functioning based mostly on their own subjective introspection – not explanatory models equally applicable to everyone. And all psychologists since Darwin have been busy dwarfs sitting on his genius shoulders, just filling in the details of his profound insight into the powerful evolutionary forces shaping our thoughts, feelings and behaviours.

Darwin recorded his first eureka moment in a casual marginal doodle penned into an 1838 notebook: ‘He who understands baboon would do more toward metaphysics than Locke’.^{Reference Darwin3} This short phrase contains the two most revolutionary ideas in psychology. First, that human nature is as much an animal inheritance as is our body morphology. Second, that much of our behaviour is influenced by inborn, unconscious drives inherited from our ancestors and selected because they were adaptive.

Darwin's other great eureka moment occurred 30 years later with his discovery of the powerful role of sexual selection in the evolution of body and mind. He phrased this foundational insight with poetic skill that rivals Lucretius:

Suicide: A Study in Sociology by Émile Durkheim (1897)

Suicide is the most personal of acts and so rare a needle in the haystack as to seem almost random. But Durkheim proved it possible to make very accurate predictions of differing suicide rates by gathering comparative data from large populations. He showed that men die by suicide more than women; singles more than marrieds; childless more than parents; Protestants more than Catholics or Jews; soldiers more than civilians; Scandinavians more than their neighbours; and the well-educated more than the poorly educated.^{Reference Durkhiem5} Although individual suicides are sporadic and unpredictable, aggregated group rates are remarkably stable over time in any given place (unless circumstances change, for example rates drop during war time and rise during economic crises). Durkheim's incredibly powerful statistical method now informs every scientific study of human behaviour.

Unfortunately, the obvious practical implications of Durkheim's findings have received far too little attention in current suicide prevention. Suicide is usually regarded as a psychological problem within the individual – despite the fact that the increasing availability of treatment during the past century has had little impact on suicide rates. We need to recognise that the basic drivers of changing suicide rates are societal (e.g. economic insecurity, drug use, gun access) and that suicide is at least as much a public health issue for the society as it is a psychological problem within an individual. Durkheim reminds us that reducing suicide rates requires reducing social disorganisation and correcting societal pathologies – not just treating mental disorders.

The History of the Peloponnesian War by Thucydides (431 bce)

There are five partly contradictory views on the predictability of history. We must know history or be doomed to repeat it. But all we learn from history is that we never learn from history. History doesn't repeat itself, but it sure does rhyme. The past is never really past. We can only see the past through the distorting lens of the present. Each is more or less true, depending on particular circumstances and how long is your view.

Thucydides is my favourite historian, perhaps because he was most self-consciously alive to its paradoxes, setting for himself what he knew to an impossible goal: ‘My work is not a piece of writing designed to meet the needs of an immediate public, but was done to last forever’ (quoted using quotation websites, not from translated text). Perhaps writing accurately about his one great war would help later generations understand the dynamics of subsequent wars and avoid their horrid consequences. He offers some hope because: ‘Human nature is the one constant through human history. It is always there’.

But Thucydides also knows better than to be so optimistic. His tragic view of history⁶ was informed by the piercing insight that its course is inherently probabilistic and contingent, not linear and predetermined. However well we know the past, it is impossible to predict the future with enough accuracy to much help in improving it. There are always too many unknown unknowns and accidental tipping points. The most vivid example is the terrible result that comes from following Pericles’ excellent advice. He was the smartest man in Athens and its most trustworthy leader. The people were swayed by his persuasive arguments in favour of war with Sparta – that Athens was impregnable because of its powerful empire and unbeatable navy. Then, in the very next chapter and without pausing for a breath, Thucydides describes the great plague of Athens that occurred just after war began, killing 100 000 people, one quarter of its population. And guess where the bugs that did the killing came from – its own empire, borne by its own ships. Sparta avoided the plague and won the war because its greatest weakness, being landlocked, turned unpredictably into its greatest strength. Who knew? Who could predict? Not Pericles. Not anyone.

Thucydides makes Machiavelli seem like an innocent schoolboy: ‘The dominant exact what they can and the weak concede what they must’. ‘Men naturally despise those who court them, but respect those who do not give way to them’. ‘Most people will not take the trouble in finding out the truth, but are much more inclined to accept the first story they hear’ (welcome to Trumpworld). And most chilling to those of us who live in fragile democracies: ‘Some legislators only wish to bring vengeance against a particular enemy. Others only look out for themselves. They devote very little time to the consideration of any public issue. They think that no harm will come from their neglect. They act as if it is always the business of somebody else to look after this or that. When this selfish notion is entertained by all, the commonwealth slowly begins to decay’.

Epic of Gilgamesh (c. 2100 bce)

Gilgamesh was the first epic novel and remains the most poignant. Our superhero is riding high and has done it all. His father was a king, his mother a goddess. He is a killer of demons, a builder of great cities, the civilizer of wild barbarians, master of his male subjects and lover to most of his female ones. Then suddenly Gilgamesh's narcissistic bubble is burst. Mourning the surprise death of Enkidu (fellow hero and best friend), Gilgamesh comes to the awful realisation that he too will someday die. Unwilling to passively accept Everyman's fate, he descends to the Underworld searching for immortality. And Gilgamesh almost has the secret within his grasp – but falls asleep at just the wrong moment and has it stolen away by a wily snake. But there is consolation in this wise advice of his to live well despite the brevity of life and the inevitability of death:

That this sounds so much like Ecclesiastes (another favourite) is no accident. Many of the Gilgamesh themes ring so familiar because Mesopotamian myths were later borrowed by nearby Jewish tribes and incorporated into the Old Testament.

Ulysses by James Joyce (1922)

Ulysses is the most realistic of novels, but also the most richly symbolic.^{Reference Joyce8} Joyce's piercing eye, empathic ear and magic tongue turn the everyday into the universal; the mundane into the magnificent; the simple into the sacred. An ordinary day in Dublin is transformed into an extraordinary tour through all of human experience and much of our myth and literature. Bloom is the most fully realised character in all literature; more alive to me than most of the people who populate my real life; lovable, warts and all, for his basic decency; fascinating in his boundless curiosity. Stephen is an uncomfortably accurate portrait of me as a very young man – all book smarts, no life wisdom, short on empathy. Molly is the earthy mother I would have wanted – someone who shouts a resounding ‘yes’ in reply to life.

A first read of Ulysses is difficult and best done with collateral help from the many useful guides available on the internet. The book is written in a dozen different, and at first blush bewildering, styles and from a hundred different points of view. But no book is better structured, more carefully plotted, so successful in meeting Aristotle's aesthetic goals of unity, harmony and radiance. No thought is too lofty, no bodily function too low, no activity too trivial to find its valued place in Joyce's world. His is the most divine rendering of the human comedy. By the second reading, Ulysses is a best friend and eventually it will become one of the loves of your life.

Alice's Adventures in Wonderland (1865) and Through the Looking Glass (1871) by Lewis Carroll

The best ‘children's books’ are the ones that grow up as you do, staying relevant in different ways at every stage of your life. As a young child, I was most fascinated by Alice's sudden size shifts from normal to very small and then to very big and her personality shifts from lost child to bossy grown-up.^{Reference Carroll9} As a teenager, trying to figure myself out, I was most struck by the Caterpillar's probing question: ‘Who are you?’ and Alice's confused answer: ‘Ah, that's the great puzzle’.^{Reference Carroll9} In my twenties, I most loved Carroll's wordplay – his ability to find so much sense in nonsense and so much nonsense in sense. In my thirties, working ridiculously long hours, it felt like: ‘Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!’.^{Reference Carroll10} In my forties, when rating psychotherapy grants for the National Institutes of Mental Health and finding all those ubiquitous tie scores in comparative studies, it seemed that ‘everybody has won and all must have prizes’.^{Reference Carroll9} In my fifties, the opinionated experts working with me on DSM-IV sounded liked this: ‘“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean – neither more nor less.” “The question is,” said Alice, “whether you can make words mean so many different things.” “The question is,” said Humpty Dumpty, “which is to be master –that's all.”’.^{Reference Carroll10} In my sixties, I most loved the logical, mathematical and scientific riddles and puzzles. And now in my seventies, I find most amusing Carroll's frequent veiled references to death.

Persuasion and Healing: A Comparative Study of Psychotherapy by Jerome Frank (1961)

I haven't included any other technical books because they rarely age well. But Jerome Frank's analysis of the healing process is timeless and should be read by everyone who heals and anyone who needs healing.^{Reference Frank11} Medicine had its origin in mysticism – with a few herbs thrown in. The shaman healed problems of body, mind and spirit by bringing the patient into his magic circle; conversing with the spirits to determine diagnosis and treatment; performing magical rituals; predicting prognosis; and finally declaring a cure. The system worked well enough to exist everywhere in the world and to survive throughout the ages despite the fact that, until very recently, all medical theories were wrong and most medical treatments were harmful, sometimes deadly. The wonderful power of expectations kept the patients coming back and made the doctors a good living.

Frank brilliantly traces how the oldest of medical rituals are still the foundations of current medical and psychiatric practice. The specific techniques change with time, but the power of the therapeutic relationship is enduring. This helps explain why there are so many tie scores in psychotherapy research and such high placebo response rates in medication studies. Great therapists are those who are able to form great relationships with their patients – not those whose noses are attached to treatment manuals. And a great common virtue of all psychotherapies is providing hope to the hopeless, remoralisation to the demoralised. Everyone in training should read this book; everyone in practice should periodically reread it; and patients will be inspired by it.

Life Ascending: The Ten Great Inventions of Evolution by Nick Lane (2010)

Having begun with Lucretius's uncannily accurate intuitions about the material nature of life, lets end with Lane's magnificent summary of its mechanisms.^{Reference Lane12} Just as Lucretius predicted, life is ridiculously complex but the trillions of tiny steps that created it were each simple and almost inevitable. Atoms of elements available just after earth's formation joined together to produce simple amino acids and small strands of RNA and DNA. Given time, a ready energy supply from the deep-sea vents, the right catalysts and containers, endless permutations of trial and error – and bingo, before very long nature produces primitive life able to replicate and metabolise. A few more blinks in geological time and bacteria evolve that are better and more versatile chemists than the professors at MIT. A few billion years later, some of these bacteria merge to form a cell with a nucleus. Then these cells start merging to form a wonderful menagerie of wildly variable multicellular creatures. And before long, nature devises the exquisite teamwork performed by the thirty trillion cells that make up the human body. In scientifically precise, but poetically expressive, terms Life Ascending describes the origin and basic mechanics of the great evolutionary inventions that make us possible – photosynthesis, sex, movement, sight, hot blood, consciousness and death.

To me, this is a much more awe inspiring, and weirdly implausible, creation story than the prosaic stuff in Genesis. Darwin put it best in his last sentence of The Origin of Species:

Parting thoughts

Heraclitus is attibuted with the saying: ‘No man ever steps in the same river twice, for it's not the same river and he's not the same man’. Similarly, no one ever reads the same great book twice because it becomes even greater on each reading as he becomes a better reader.

Medicine and literature were once kindred professions. Let's close with another apt quote from Epictetus: ‘Don't just say you have read books. Show that through them you have learned to think better, to be a more discriminating and reflective person. Books are the training weights of the mind’.