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‘Do No Harm’: Henry Marsh gives the 2018 Voltaire Lecture

Yesterday an audience of almost 900 people turned out at the Camden Centre in London to hear the 2018 Voltaire Lecture, which was given by best-selling author, renowned neurosurgeon, and Humanists UK patron Dr Henry Marsh. As per tradition, the Voltaire Lecture was chaired by the President of Humanists UK, comedian and author Shappi Khorsandi.

A crowded theatre for the ‘Do No Harm’ author

Entitled ‘Do No Harm,’ Henry’s lecture explored the theme of his book of the same name, which was a memoir of sorts examining the moral complexities and difficulties encountered by medical physicians in the course of their work. In his lecture, Henry expressed with remarkable a clarity a few the complex dilemmas which many health practitioners inevitably face. Tensions arise, for example, between a patient’s need for certainty from their doctors and a medical professional’s need to think about health outcomes, and modes of treatment, in degrees of probability. ‘The surgical decision is always uncertain,’ said Henry. ‘It is not clear-cut… So much of modern medicine is palliative and not about saving a life, but improving life.’ When faced with the choice between saving a life, and at the same time taking away a person’s quality of life, as so often neurosurgeons must consider, surgeons are faced with ‘competing moral calculations’ in the absence of instructions from their patient. The anxiety a doctor faces when recommending treatment can be all the worse when they know, as most do, that human beings are riven with cognitive biases and irrational, personal leanings which often lead us away from making a purely fair calculation of harm, despite our best efforts to be objective.

Henry opened his talk with an examination of the Hippocratic Oath – famously reported as First do no harm – which doctors historically swear by, and the amusing fact that Hippocrates, after whom it is named, never included an imperative to do no harm. Fittingly for the Voltaire Lecture, he pointed instead to a quotation from Voltaire which he said more accurately portrayed medicine as practised for most of its history: ‘The art of medicine consists in amusing the patient while nature cures the disease.’ For much of human history, medical practice was largely non-scientific, and as such harm was a frequent byproduct of medical intervention. Much like Voltaire, the Russian playwright Anton Chekhov espoused a cynical view: ‘Doctors are the same as lawyers; the only difference is that lawyers merely rob you, whereas doctors rob you and kill you too.’

Shappi Khorsandi chaired the event

Today’s medical science is remarkably more advanced than it was in the 18th or 19th centuries, when Voltaire and Chekhov lived. But still the imperative ‘First do no harm’ fails to account for the sorts of nuanced decisions that are par for the course for doctors and particularly for surgeons. For example, when a surgeon knows that in their lifetime they will have a duty not only to their present patients but also to potentially thousands more, this invites a sort of cognitive dissonance – encouraging a kind of overconfidence, even in the face of risky procedures one has not attempted before, because it is only through trial, error, and practice that doctors improve and surgical procedures are perfected. The practice of medicine, to some extent, relies on doctors accepting this contradiction. In an unflinchingly honest take on his own history of practice in medicine, Henry spoke of his many regrets, alluding to the French surgeon René Leriche’s quotation that ‘Every surgeon carries within them a small graveyard.’

Elsewhere in his talk, Henry spoke about the difficulties faced by senior staff and junior doctors alike in the NHS, litigation culture, and his worries that an over-reaching regulatory framework – often updated in response to particular high-profile crises or instances of malpractice – are making the doctor-patient relationship increasingly strained and less sincere. He also reflected on how his career shaped his personal views, and helped him arrive at a humanist view of life, saying ‘As a brain surgeon, you find the idea of an afterlife very hard to believe in.’

The lecture had no shortage of compassionate, sage advice for others looking to enter the profession. Reflecting on Leriche’s remark and his own ‘vast inner graveyard’, Henry attempted to answer the question: ‘What would you do differently?’ Ask for advice and help a bit more, Henry said. Not necessarily because your colleagues will know better than you, he explained, but often because simply asking for help can in itself be a positive step. Sharing concerns with colleagues will often flag up blind spots in your reasoning, because they will have different perspectives and experiences from you, and will not share your unique complex of biases. In medicine, the ability to overcome one’s biases can save a life – or potentially spare someone a great deal of suffering.


At Humanists UK, we advance free thinking and promote humanism to create a tolerant society where rational thinking and kindness prevail. Our work brings non-religious people together to develop their own views, helping people be happier and more fulfilled in the one life we have. Through our ceremonies, education services, and community and campaigning work, we strive to create a fair and equal society for all.

The Voltaire Lecture was established by the legacy of Theodore Besterman, biographer of Voltaire, for lectures on ‘any aspect of scientific or philosophical thought or human activity as affected by or with particular reference to humanism.’ Previous Voltaire lecturers have included: Professor Sir David King, Professor Anthony Grayling, Professor Steven Pinker, Professor Brian Cox, Professor Richard Dawkins, Professor Robert Hinde, Baroness Wootton, Bettany Hughes, Michael Foot, Kenan Malik, Natalie Haynes, Bonya Ahmed, Lord Taverne, Nick Cohen, and Sir Ludovic Kennedy. It is always chaired by the President of Humanists UK.

The 2018 Voltaire Lecture was recorded and will be uploaded to YouTube at a later date.

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