Charles Darwin made a list of pros and cons before proposing to his cousin Emma, fretting that a wife would mean less money for books, and on the pro side he wrote that a constant companion was better than a dog anyhow

In the summer of 1838, Charles Darwin was 29, back from five years on the Beagle, and living alone in London. He was also stuck on a question. So he did what a careful scientist might do: he took a scrap of paper, wrote “This is the Question” across the top, and drew two columns headed “Marry” and “Not Marry.”

The result, now held at Cambridge University Library, is one of the most quoted documents in his whole archive. It’s funny, a little unflattering, and surprisingly revealing about how people try to reason their way through decisions that may not fit neatly into reason.

What was actually on the list

The “Marry” column starts with children, then lists a constant companion and friend in old age, “who will feel interested in one.” Squeezed in between the lines, Darwin added that such a companion would be “better than a dog anyhow.” He also listed a home, someone to look after it, and the “charms of music & female chit-chat,” though he immediately added that all this meant a “terrible loss of time.”

The “Not Marry” column is mostly about freedom and work. It covers the freedom to go where he liked, avoiding forced visits to relatives, and keeping his evenings for reading. Then come the money worries: anxiety, responsibility, and “less money for books &c.” You can read the full transcription at the Darwin Correspondence Project.

Under both columns, he wrote his verdict: “Marry—Mary—Marry Q.E.D.” That’s the Latin abbreviation mathematicians use at the end of a proof, meaning “which was to be demonstrated.” Then, on the same page, he moved straight on to the next problem, which was when.

Darwin was following a famous method

Darwin wasn’t the first to treat a life choice as a sum. In 1772, Benjamin Franklin wrote to his friend Joseph Priestley with advice on making hard decisions. He suggested dividing a sheet of paper into two columns, pros and cons, adding reasons over several days, then crossing out items of roughly equal weight on each side until it became clear where the balance lay. Franklin called it “moral or prudential algebra.”

The idea behind it is appealing. Big decisions overwhelm us partly because we can’t hold all the considerations in mind at once. Writing them down stops one vivid worry from crowding out everything else. Darwin’s list does exactly that, setting the pleasant image of a fire and a sofa against the fear of losing time for science.

The problem with weighing a future self

Philosophers have pointed out a deeper difficulty with lists like this, though. The American philosopher L.A. Paul calls certain choices “transformative experiences.” In her 2014 book of the same name, she argues that some decisions, like becoming a parent, change you so deeply that you can’t know beforehand what the experience will be like. You also can’t know what you’ll value once you’re on the other side.

Darwin’s list shows this clearly. The bachelor writing it was weighing marriage by a bachelor’s standards: books, evenings, freedom, money. He couldn’t consult the man he’d become after decades with Emma and ten children, because that man didn’t exist yet. In his first set of notes from earlier that year, he’d even worried that married life might mean “no books” at all.

As it turned out, the dire predictions in the “Not Marry” column didn’t really come true. Darwin did his most important work as a married man, at home in Kent. Family money meant he was never “forced to gain one’s bread.”

The name that’s missing

There’s another odd thing about the list. For a document written while he was thinking about proposing to Emma Wedgwood, it barely mentions her. The “Marry” column describes a wife in general: a companion, a homemaker, someone to play music. Emma’s own personality, opinions and wishes don’t appear at all, and the decision is framed as Darwin’s alone.

Historians have pointed out that this reflects the assumptions of a well-off Victorian man as much as a scientific mind. It also exposes a limit of the pros-and-cons approach. A list is good at weighing categories, such as “a wife,” “children” or “less money.” It’s much worse at capturing a particular person, which is usually what the decision is really about.

Kierkegaard’s warning

A few years later, in 1843, the Danish philosopher Søren Kierkegaard published Either/Or, which includes a famous mock lament along the lines of: marry and you’ll regret it, don’t marry and you’ll regret that too. His point was half joke, half serious. Some choices can’t be settled by tallying advantages, because every path closes off another, and something will be lost either way.

Read alongside Kierkegaard, Darwin’s “Q.E.D.” looks a bit like a man trying to prove something that can’t really be proved. The list didn’t make the decision for him so much as give him permission to make it.

What the list is good for

That doesn’t make Darwin’s list useless, or silly. Writing down the worries, even the slightly embarrassing ones about money and books, let him see that they were real but not decisive. Franklin’s method works best that way: as a way to stop fears from hiding, not as a machine that spits out the answer.

Emma accepted his proposal on November 11, 1838, and Darwin wrote “The day of days!” in his journal. They married the following January and stayed together for 43 years, until his death in 1882. Whatever the columns said, it seems the deciding factor wasn’t on the page.