Why Did Darwin Wait 20 Years to Publish? The Slow Road to On the Origin of Species

Charles Darwin (1809–1882) worked out the core of his theory of natural selection in 1838, but he did not publish it in full until On the Origin of Species appeared in 1859. He waited partly because he wanted overwhelming evidence for an idea he knew would be controversial, partly because he kept taking on other huge projects, and partly because he was frequently ill. What finally forced his hand was a letter: in 1858 the naturalist Alfred Russel Wallace sent him an essay describing almost the same theory. Here is the long, very human story of how one of the most important ideas in science reached the world.

A doctor who couldn't watch surgery

Darwin was born on 12 February 1809 in Shrewsbury, England, into a comfortable family. His father, a doctor, sent him to the University of Edinburgh to study medicine. Darwin found the lectures dull and the surgery, performed without anaesthetic, horrifying, and he left the course.

He then went to Christ's College, Cambridge, with the idea of becoming a country clergyman. What he really loved, though, was natural history: collecting beetles, going on geology field trips and talking with naturalists. That passion would soon take him around the world.

Five years on the Beagle

In 1831 Darwin joined HMS Beagle on a survey voyage that lasted five years, until 1836. The ship's main job was to chart coastlines, especially in South America, which gave Darwin long stretches ashore to collect fossils, rocks, plants and animals.

The voyage established him as a geologist and naturalist. He found fossils of giant extinct mammals, experienced an earthquake in Chile and saw how land could rise over time. On the Galápagos Islands he noticed that similar animals differed from island to island, observations that later helped shape his thinking about how species change.

The big idea: 1838

Back in England, Darwin began filling private notebooks with ideas about how species might change. In 1838 he read Thomas Malthus's essay on population, which argued that populations tend to grow faster than their food supply, leading to a constant struggle for existence. That gave Darwin the mechanism he was looking for.

The idea of natural selection can be summarised in a few steps:

1. Individuals in a population vary.
2. Some of that variation is inherited.
3. More are born than can survive.
4. Individuals with useful variations are more likely to survive and reproduce.
5. Over many generations, those useful traits become more common, and populations change.

Simple to state, enormous in its consequences.

Twenty years of evidence (and other projects)

Why not publish immediately? Darwin knew that an explanation of life without separate acts of creation would provoke fierce objections, both scientific and religious, so he set out to gather an overwhelming case. He also kept busy with other major work. He spent years on a detailed study of barnacles, among other projects. And for most of his adult life he suffered from chronic illness that often stopped him from working.

His personal life was settled and devoted. He married his cousin Emma Wedgwood in 1839, and they had ten children. The family lived in the village of Downe in Kent, where Darwin ran experiments in his garden and greenhouse and wrote thousands of letters to collectors and scientists around the world.

Wallace's letter

In 1858 Darwin received an essay from Alfred Russel Wallace, a younger naturalist working in the Malay Archipelago, describing a theory of natural selection remarkably like his own. Darwin was shocked. Friends arranged for both men's work to be presented together to the Linnean Society of London that year.

The arrangement is often seen as fair to both, and Wallace remained respectful of Darwin for the rest of his life. But it also pushed Darwin to stop collecting and start writing.

On the Origin of Species

Darwin wrote quickly what he called an "abstract" of his planned bigger book. It was published in 1859 as On the Origin of Species. The book presented natural selection with a mass of supporting evidence from breeding, geography, fossils and anatomy, and it sold out quickly.

Interestingly, the first edition said very little directly about humans. Darwin addressed human evolution later, in The Descent of Man (1871), where he also developed the idea of sexual selection. He went on writing until the end, on topics from emotional expression to orchids to earthworms.

Legacy

Darwin died at Downe on 19 April 1882 and was buried in Westminster Abbey, close to Isaac Newton. His theory, combined later with genetics, became the foundation of modern biology. His long delay is a reminder that great ideas usually need years of patient checking before they are ready for the world.

Learn with Darwin: English phrases about ideas and evidence

Phrase	Meaning	Example
to force someone's hand	to make someone act sooner than planned	The deadline forced my hand.
to build a case	to collect evidence for an argument	She built a strong case for the new plan.
survival of the fittest	(popular phrase) the best-adapted succeed	In this market, it's survival of the fittest.
to sit on an idea	to keep an idea without acting on it	He sat on the idea for years.
to adapt to	to change to suit new conditions	I'm still adapting to life abroad.

Try this: Think of an idea you have been "sitting on", such as a trip, a course or a habit. Write three English sentences explaining why you waited and what could "force your hand".