After 378 pages of intensely intricate logical proofs, one comes upon a triumphant sentence: ‘From this proposition it will follow, when arithmetical addition has been defined, that 1 + 1 = 2.’ The purpose of Bertrand Russell’s Principia Mathematica (1910-13), co-authored with Alfred North Whitehead, was to find a logical foundation for mathematics, what is known as the logicist programme. In pursuit of this, the book took 10 years to write and launched modern mathematical logic. For the lay reader, it is the height of esoteric philosophy: hundreds and hundreds of pages of dense logical symbolism, much of which the authors created specifically for their purposes. That is why it comes as something of a surprise to learn that Russell’s political activism earned him two bouts of jail time – one in 1918, the other in 1961. There are not many logicists so willing to get their hands dirty in the muck of the real world. But Russell was much more than a mere philosopher.

In this 1959 interview from the BBC programme Face to Face, Russell recounts episodes of his long and spectacular life. Born in 1872 to a powerful family (his grandfather was a prime minister), he involved himself in many of the most significant political issues of the next century, from the First World War to the Six-Day War, always from a liberal or Left perspective. He was a passionate pacifist (the stance that can be partially blamed for his jail sentence in 1918), an atheist, and supremely moral man whose passion for knowledge was matched only by his empathy for his fellow human. ‘It just won’t do to live in an ivory tower,’ Russell says. ‘This world is too bad, and we must notice it.’