#87 Charles Darwin – Hosts of Living Forms

When I last wrote about Darwin, I said it was difficult to write about something we now agree is obviously true, and which forms one of the core blocks of our understanding of the universe.* It’s even more true with this volume, which mostly consists of Darwin explaining away the most likely criticisms of his new theory.

For example, Darwin spends most of a chapter explaining how species could find their way from nearby landmasses to isolated islands. Nowadays, not only do we accept his argument, but we can actually turn it around and say that the presence of certain species or particular fossils is a good clue as to where a particular landmass has been drifting over the past billion or so years. For me to find fault in what he is saying, I would need to know a lot more about biology than I am ever likely to pick up.

But one thing that does appeal is how Darwin goes about proving his case. Having read so many philosophers in this series, who sit at their writing desk and assert what they believe to be true, it’s refreshing to come across a scientist. When Darwin has a question, he looks for proof.

For example, he feels one of the weaknesses of his argument is explaining how similar species can be living in freshwater rivers near each other, given that they can’t get from one river to the next without going through an environment that for some would probably be lethal. Part of his answer relies on mud carried on the feet of birds, and to prove that he’s not just talking nonsense, he puts it to the test.

“I took in February three table-spoonfuls of mud from three different points, beneath water, on the edge of a little pond; this mud when dry weighed only 6¾ ounces; I kept it covered up in my study for six months, pulling up and counting each plant as it grew; the plants were of many kinds, and were altogether 537 in number; and yet the viscid mud was all contained in a breakfast cup!”

Following a similar question, he goes down to the coast to submerge seeds in sea-water, to see whether they stand a chance of crossing the ocean; in another he dunks land-shells to see if they can live for the time it might take to reach a new home. In both cases he is proved right, and what would otherwise simply be assertions can be treated potentially as facts.

The other remarkable thing about Darwin is just how capacious his knowledge is. In the world of wikipedia, we forget just how rare information used to be. To get scientific information, you actually had to be able to hold a book about it in your hands, or else you had to experience it first-hand. But Darwin is quoting an entire world of botany. Obviously, there’s the fruits of his own visit to the Galapagos islands; yet he also talks about Madeira, Bermuda, Sicily, New Zealand and an equally exotic host of other places.** There’s also a vast range of fossil information supporting what he says about the history of life.

The remarkable thing is not just that Darwin reached such a radical conclusion, but that there was the evidence there to back it up. There’s more to what he did than staring at a few finches and having a clever idea about how they got their beaks – it’s a product of a vast, supporting scientific culture that could stock his library with books and pose him the awkward questions he needed to resolve if he wanted his theory to be credible.

All of which makes me think of Darwin as a bit of a scientific hero – learned and adventurous, intuitive and testing, always ready to critique what he was saying and ready to address his weaknesses.*** Almost sorry to be showing others to be wrong. And, as I’ve said before, he wasn’t a bad writer either. What an irony that he should be the one to come up with the most controversial idea of all history.

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* Disagree if you want. But I note in passing that most of the arguments for neo-creationism are pretty much the same as when Darwin answered them a hundred and sixty years ago. The only thing that hasn’t evolved is them.

**And Belgium.

*** “If I looked far, it was because I was standing on the shoulders of giant tortoises”, as he didn’t quite say.