In the 1960s and 70s, a revolution took place in the way we understand human nature. Out went Marx and Freud, and in came a rational, scientific approach to the way we see ourselves. At the vanguard of that revolution was Richard Dawkins, the evolutionary biologist whose book The Selfish Gene changed the thinking not just of other scientists but of all of us, and propelled its author to intellectual stardom as the modern heir to Darwin.

To mark the 40th anniversary of The Selfish Gene and Dawkins’ 75th birthday, Intelligence Squared staged a global event, bringing together luminaries from the worlds of science, philosophy and culture to engage with Dawkins about his life and work. Steven Pinker, celebrated cognitive scientist, and Daniel Dennett, philosopher and fellow ‘New Atheist’, was beamed in live from America. Stephen Fry paid tribute via a special recorded message. On-stage guests include the illusionist Derren Brown, an avowed fan of Dawkins’ theories about the workings of the mind, the science writer Susan Blackmore, who has further developed some of Dawkins’ important ideas, and the acclaimed novelist and playwright Michael Frayn.

It was Dawkins’ understanding of the gene as the fundamental unit of natural selection that captured the popular imagination. It was Dawkins, too, who invented the word ‘meme’ to describe the cultural equivalent of a gene – an idea, belief or practice that replicates itself from person to person and is subject to the same selective pressures as genes – whether it’s an age-old religious practice or a modern fad such as the ice bucket challenge.

And on the subject of religion, the publication of The God Delusion a decade ago marked the moment when Dawkins became the patron saint of atheism. The book turned him into the world’s leading controversialist – hero-worshipped by atheists, demonised by believers. But throughout the hubbub of being the celebrity scientist and the non-believers’ poster boy, Dawkins continued his scientific studies at New College, Oxford, and in obscure corners across the world – where he honed the art of observing and writing beautifully about nature, conveying his sense of wonder at how organisms developed their complexity over the ages.

Here we gathered some of the world’s most original and incisive minds as they celebrated the man who has probably done more than any other person alive to illuminate how we think about ourselves and the world around us.