David Stack, Head of History at Reading, writes:


On 24 November 1859 a book containing ‘the best idea anybody ever had’ was published. Charles Darwin’s On the Origin of Species by means of natural selection had been twenty-one years in the making and was written in a hurry.

Over a century and half later the significance of the book is (almost) universally acknowledged, but still often misunderstood.

The Origin did not introduce the idea of evolution. Evolutionary ideas had been around since the time of Aristotle, and in the ‘Historical Sketch’ which Darwin added to the third edition of the Origin he identified over 30predecessors). Nor did it announce the death of God, Darwin was still a theist when he wrote the Origin. And far from proclaiming that men were descended from monkeys, the Origin avoided the subject of human evolution altogether until two pages before the end, where Darwin tantalised his readers with the enigmatic comment that if his theory proved to be true ‘Light will be thrown on the origin of man and his history’.

What then was the significance of the Origin? Why did it matter? And why does it still matter today? The answer is simple: because in ‘one long argument’ the Origin outlined the mechanism by which evolution works: natural selection. This was what the philosopher Daniel Dennett meant by ‘the best idea anybody ever had’.

Whereas earlier evolutionary accounts had been teleological, the Origin showed that evolution worked by an unscripted process of variation, branching, and differential survival rates. Nature was a ‘struggle for existence’, and evolution occurred by a merciless ‘survival of the fittest’ (the phrase was Herbert Spencer’s, but was incorporated by Darwin into the 1869 edition of the Origin) in which the best adapted survived and passed on their relative advantages to their offspring.

On page after page of the Origin, Darwin showed by example laid upon example, how feature after feature of the natural world could be explained not by Special Creation or an interventionist Creator, but by the simple incremental process of natural selection. This did not demand the death of God: the Origin was concerned with the origin of species – i.e. with explaining divergence and variety – not the origin, let alone the meaning, of life. But Darwin did demand the death of Design.

The target he had in his sights was the Anglican theologian William Paley whose ‘watchmaker analogy’ was the foundation of both nineteenth century natural theology and science. Science and religion, it should be remembered, were not at war in the early nineteenth century. They were at one in reasoning from Nature up to Nature’s God. As an undergraduate Darwin in the 1820s had occupied Paley’s old rooms in Christ’s College, Cambridge, and had been impressed by the theologian’s arguments. By 1838 he had hit upon natural selection as the mechanism to explain evolutionary change.

But if Darwin had, as he later put it, ‘a theory by which to work’ in 1838, why did he then wait twenty-one years before telling the world? The question has divided historians in recent years, with ‘internalists’ stressing Darwin’s proper scientific caution, and ‘externalists’ suspecting Darwin’s acute awareness of the potential social and political consequences – for himself, for his family, and for society –  of unleashing his dangerous idea.

Whichever explanation one favours — and as is the case in most historiographical disputes, the truth probably lies somewhere in between two caricatured extremes – what is undeniable is that the delay made the Origin a better book. It allowed Darwin to flesh out his understanding and systematically work through possible objections. As a result one of the most persuasive features of the Origin is Darwin’s ability to anticipate objections and tackle them head on. Indeed, much of the book is a master class in anticipatory refutation. Even some of the chapter titles – ‘Difficulties on Theory’, ‘On the Imperfection of the Geological Record’ – acknowledged the difficulties he faced, and indicated his determination to rebut every possible criticism.


Why then was this work, so long in the making, ultimately written in a hurry? The answer is three words: Alfred Russel Wallace. The ‘perennial afterthought’ in histories of evolution, Wallace was a naturalist working in the field in south-east Asia, who during a bout of malaria had an idea for a scientific paper, which he entitled ‘On the tendency of species to depart indefinitely from the original type’, and sent it to Darwin in June 1858. When Darwin read the paper he was flabbergasted. Wallace too had hit upon the theory of evolution by natural selection. ‘All my originality, whatever it may amount to,’ Darwin wailed, ‘will be smashed’.

He would delay no longer. His plan for a multi-volume doorstopper to be entitled Natural Selection was set aside, and he set to work on a crisply composed outline sketch. Darwin proposed calling it An Abstract of an Essay on the Origin of Species and Varieties through Natural Selection, until his publisher demanded something snappier.

It is often said that the Origin sold out on the day of publication. This is not quite true. Darwin was no J.K. Rowling, but all 1,250 copies were taken by booksellers and a second edition was in print by January 1860. Four further editions, all slightly modified, appeared in Darwin’s lifetime, and the Origin has never been out of print since.

There is no better way to mark the 155th anniversary of the Origin than by sitting down to read it. Some of the detail of the science is now outdated (largely because subsequent scientists stood so squarely on Darwin’s shoulders), but that is beside the point. The construction of Darwin’s argument is exemplary; the prose is often poetic; his examples are occasionally startling; and his protests against Paleyan Design are as good a riposte to contemporary Creationists and ‘Intelligent Designers’ as you will find. Most of all I defy anyone to read the Origin with an open mind and not share the awe and admiration of Darwin’s insight with which the Origin concludes: “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”