On the Origin of Species, the slowest breeder

Charles Darwin published On the Origin of Species on November 24, 1859, in a first printing of 1,250 copies. Darwin worked on the argument for more than twenty years before printing it, and filled notebook after notebook with breeding figures like these. Darwin’s elephant calculation shows how fast even the slowest animals multiply.

Where this text comes fromThis is arithmetic used as an argument. Darwin picks the animal that breeds most slowly, works out what would happen if even that animal reproduced without check, and lets the number do the persuading. The calculation is deliberately conservative, because a skeptical reader can dismiss a fast-breeding example as a special case but cannot dismiss the slowest one. He had been assembling figures of this kind for two decades before the book appeared, and the notebooks are full of them.

What you might not noticeThe whole calculation runs as a single sentence of eighty-three words, and it names no digits at all. Every number in the passage is spelled out in letters. Source

What it trainsEighty-three words with no full stop until the end, held together by five commas, one colon and one semicolon. The colon is the hinge: everything before it sets up the problem and everything after it works the sum. Only two capital letters appear in 456 characters, one of them inside the sentence. Because the passage is doing arithmetic in words rather than figures, the number row is never used, and the difficulty is holding a long conditional clause without losing which condition you are inside.

Read the full text at the publisher: Project Gutenberg