The Eight Years Darwin Spent on Barnacles

In 1846 Charles Darwin, who already held an outline of a theory that could explain the origin of species, began studying barnacles. He spent about eight years on them, and in September 1854 his last barnacle monograph was ready for publication. During that time the idea that would make him famous waited in a drawer. He had expanded his 1842 sketch into a longer essay in 1844, and then he put the matter away.

Why would a man with such an idea spend eight years on creatures that most people never notice? One answer is that he was avoiding the risk. A theory of species touched religion and politics, and Darwin knew the fury it might bring. Barnacles were safe, and delay can look like a virtue when it is really a form of fear.

A second answer is that barnacles were exactly what he needed. A theory of species could hardly be taken seriously from a man who had never classified a group himself, and the great variation within barnacles gave him a close view of how living forms differ. On this account the years were an apprenticeship, and the patience was real. The work earned him a medal from the Royal Society and a reputation among naturalists.

delay can look like a virtue when it is really a form of fear.

A third answer is that the delay was never fully planned. Illness often kept him from work, and he wanted to meet likely objections before publishing. In June 1858 a parcel from Alfred Russel Wallace described a similar mechanism, and the choice was taken out of his hands. Extracts from Darwin's earlier writings were read with Wallace's paper to the Linnean Society on 1 July, and On the Origin of Species appeared on 24 November 1859.

Historians still disagree about which answer is correct, and Darwin's own motives were probably mixed. What the story shows is how hard it is to tell patience from avoidance when only the outcome is visible. A long delay that ends in a masterpiece is called wisdom, and the same delay that ends in a rival's priority would have been called cowardice.