For the moment, let’s set aside the question of why I was reading a review titled “Plants Neither Possess nor Require Consciousness.” Instead, I’d like to share a passage from the end of the article:
Plant neurobiologists are hardly the first biologists to ascribe consciousness, feelings, and intentionality to plants.
Erasmus Darwin, [Charles] Darwin’s grandfather and a believer in free love, was so taken with the Linnaean sexual system of classification that he wrote an epic poem, The Loves of Plants, in which he personified stamens and pistils as ‘swains’ and ‘virgins’ cavorting on their flower beds in various polygamous and polyandrous relationships.
Maybe you were startled, just now, to learn about the existence of risqué plant poetry. Do some people log onto Literotica to read about daffodils or ferns?
But what caught my attention was Erasmus Darwin’s designation as a believer in free love.
In a flash, an entire essay composed itself in my mind. Charles Darwin’s grandfather was a polyamorist! Suddenly, the origin of The Origin of the Species made so much more sense! After all, exposure to polyamory could help someone notice evolution by natural selection. An essential component of polyamory is freedom of choice – during the 1800s, when nobody had access to effective birth control, people might wind up having children with any of their partners, not just the one with whom they were bound in a legally-recognized and church-sanctioned marriage.
Evolution occurs because some individuals produce more offspring than others, and then their offspring produce more offspring, and so on. Each lineage is constantly tested by nature – those that are less fit, or less fecund, will dwindle to a smaller and smaller portion of the total population.
Similarly, in relationships where choice is not confined by religious proscription, the partners are under constant selective pressure if they hope to breed. When people have options, they must stay in each other’s good graces. They must practice constant kindness, rather than treating physical affection as their just desserts.
I felt proud of this analogy. To my mind, Erasmus Darwin’s belief in free love had striking parallels with his grandson’s theory.
And it’s such a pleasure when essays basically write themselves. All I’d need to do was skim a few biographies. Maybe collect some spicy quotes from Erasmus himself. And I’d try to think of a clever way to explain evolution to a lay audience. So that my readers could understand why, once I’d learned this juicy tidbit about Erasmus, his connection to Charles Darwin’s theory seemed, in retrospect, so obvious.
My essay failed.
I wish it hadn’t, obviously. It was going to be so fun to write! I was ready to compose some sultry plant poetry of my own.
And I feel happy every time there’s another chance to explain evolution. Because I live in a part of the United States where so many people deny basic findings from science, I talk about this stuff in casual conversations often. We regularly discuss evolutionary biology during my poetry classes in jail.
But my essay wasn’t going to work out. Because the underlying claim – Erasmus Darwin believed in free love! – simply isn’t true.
Maybe you have lofty ideals about the practice of science. On the children’s record Science Is for Me, Emmy Brockman sings:
I am a scientist
I explore high and low
I question what I know
That’s the goal. A good scientist considers all the possibilities. It’s hard work, making sure that confirmation bias doesn’t cause you to overlook alternative explanations.
But scientists are human. Just like anybody else, we sometimes repeat things we’ve heard without considering whether any evidence ever justified it.
In The Human Advantage, neuroscientist Suzana Herculano-Houzel describes how baffled she felt when she began reading scientific papers about the composition of our brains.
Although the literature held many studies on the volume and surface area of the brain of different species, and various papers on the densities of neurons in the cerebral cortex, estimates of numbers of neurons were scant. In particular, I could find no original source to the much-repeated “100 billion neurons in the human brain.”
I later ran into Eric Kandel himself, whose textbook Principles of Neural Science, a veritable bible in the field, proffered that number, along with the complement “and 10-50 times more glial cells.” When I asked Eric where he got those numbers, he blamed it on his coauthor Tom Jessel, who had been responsible for the chapter in which they appeared, but I was never able to ask Jessel himself.
It was 2004, and no one really knew how many neurons could be found on average in the human brain.
Unsatisfied with the oft-repeated numbers, Herculano-Houzel liquified whole brains in order to actually count the cells. As it happens, human brains have about 86 billion neurons and an equal number of glial cells.
Or, consider the psychology experiments on behavioral priming. When researchers “prime” a subject, they inoculate a concept into that person’s mind.
The basic idea here is relatively uncontroversial. It’s the principle behind advertising and paid product placement – our brains remember exposure while forgetting context. That’s why political advertisements try to minimize the use of opponents’ names. When people hear or see a candidate’s name often, they’re more likely to vote for that candidate.
Facebook has also demonstrated again and again that minor tweaks to the inputs that your brain receives can alter your behavior. One shade of blue makes you more likely to click a button; there’s a size threshold below which people are unlikely to notice advertisements; the emotional tenor of information you’re exposed to will alter your mood.
When research psychologists use priming, though, they’re interested in more tenuous mental links. Study subjects might be primed with ideas about economic scarcity, then assessed to see how racist they seem.
The first study of this sort tested whether subconsciously thinking about elderlies could make you behave more like an elderly person. The researchers required thirty undergraduate psychology students to look at lists of five words and then use four of these words to construct a simple sentence. For fifteen of these students, the extra word was (loosely) associated with elderly people, like “Florida,” “worried,” “rigid,” or “gullible.” For the other fifteen, the words were deemed unrelated to elderlies, like “thirsty,” “clean,” or “private.”
(Is a stereotypical elderly person more gullible than private? After reading dozens of Mr. Putter and Tabby books — in which the elderly characters live alone — I’d assume that “private” was the priming word if I had to choose between these two.)
After completing this quiz, students were directed toward an elevator. The students were timed while walking down the hallway, and the study’s authors claimed that students who saw the elderly-associated words walked more slowly.
There’s even a graph!
This conclusion is almost certainly false. The graph is terrible – there are no error bars, and the y axis spans a tiny range in order to make the differences look bigger than they are. Even aside from the visual misrepresentation, the data aren’t real. I believe that a researcher probably did use a stopwatch to time those thirty students and obtain those numbers. Researchers probably also timed many more students whose data weren’t included because they didn’t agree with this result. Selective publication allows you to manipulate data sets in ways that many scientists foolishly believe to be ethical.
If you were to conduct this study again, it’s very unlikely that you’d see this result.
Some scientists are unconcerned that the original result might not be true. After all, who really cares whether subconscious exposure to words vaguely associated with old people can make undergraduates walk slowly?
UCLA psychology professor Matthew Lieberman wrote,
What we care about is whether priming-induced automatic behavior in general is a real phenomenon. Does priming a concept verbally cause us to act as if we embody the concept within ourselves? The answer is a resounding yes. This was a shocking finding when … first discovered … in 1996.
Lieberman bases this conclusion on the fact that “Hundreds of studies followed showing that people primed with a stereotype embodied it themselves.” Continued success with the technique is assumed to validate the initial finding.
Unfortunately, many if not most of those subsequent studies are flawed in the same way as the original. Publication biases and lax journal standards allow you to design studies that prove that certain music unwinds time (whose authors were proving a point) or that future studying will improve your performance on tests today (whose author was apparently sincere).
Twenty years of mistaken belief has given the walking speed study – and its general methodology – an undeserved veneer of truth.
Erasmus Darwin didn’t believe in free love. But he did have some “radical” political beliefs that people were unhappy about. And so, to undermine his reputation, his enemies claimed that he believed in free love.
Other people repeated this slander so often that Erasmus Darwin is now blithely described as a polyamorist in scientific review articles.
So, why did conservative writers feel the need to slander Erasmus Darwin? What exactly were his “radical” beliefs?
Erasmus Darwin thought that the abject mistreatment of black people was wrong. He seems to have thought it acceptable for black people to be mistreated – nowhere in his writings did he advocate for equality – but he was opposed to the most ruthless forms of torture.
Somewhat. His opposition didn’t run so deep that he’d deny himself the sugar that was procured through black people’s forced labor.
And, when Erasmus Darwin sired children out of wedlock – which many upper-class British men did – he scandalously provided for his children.
In British society, plenty of people had affairs. Not because they believed in free love, but because they viewed marriage as a fundamentally economic transaction and couldn’t get a divorce. But good British men were supposed to keep up appearances. If a servant’s child happened to look a great deal like you, you were supposed to feign ignorance.
Even worse, the illegitimate children that Erasmus Darwin provided for were female. Not only did Darwin allow them to become educated – which was already pretty bad, because education made women less malleable spouses – but he also helped them to establish a boarding school for girls. The contagion of educated women would spread even further!
This was all too much for Britain’s social conservatives. After all, look at what happened in France. The French were unduly tolerant of liberal beliefs, and then, all of a sudden, there was murderous revolution!
And so Erasmus Darwin had to be stopped. Not that Darwin had done terribly much. He was nationally known because he’d written some (mediocre) poetry. The poetry was described as pornographic. It isn’t. Certain passages anthropomorphize flowers in which there are unequal numbers of pistils and stamens. It’s not very titillating, unless you get all hot and bothered by the thought of forced rhymes, clunky couplets, and grandiloquent diction. For hundreds of pages.
While reading about Erasmus Darwin, I learned that some people also believe that he was the actual originator of his grandson’s evolutionary theories. In a stray sentence, Erasmus Darwin did write that “The final course of this contest between males seems to be, that the strongest and most active animal should propagate the species which should thus be improved.” This does sound rather like evolution by natural selection. But not quite – that word “improved” hints at his actual beliefs.
Erasmus Darwin did believe all life had originated only once and that the beautiful variety of creatures extant today developed over time. But he thought that life changed from simple to complex out of a teleological impulse. In his conception, creatures were not becoming better suited to their environment (which is natural selection), but objectively better (which isn’t).
I’m not arguing that Charles Darwin had to be some kind of super genius to write The Origin of the Species. But when Charles Darwin described evolution, he included an actual mechanism to rationalize why creatures exist in their current forms. Things that are best able to persist and make copies of themselves eventually become more abundant.
That’s it. Kind of trivial, but there’s a concrete theory backed up by observation.
Erasmus Darwin’s belief that life continually changed for the better was not unique, nor did it have much explanatory power.
In the biography Erasmus Darwin, Patricia Fara writes that,
By the end of the eighteenth century, the notion of change was no longer in itself especially scandalous. For several decades, the word ‘evolution’ had been in use for living beings, and there were several strands of evidence arguing against a literal interpretation of the Bible. Giant fossils – such as mammoths and giant elks – suggested that the world had once been inhabited by distant relatives, now extinct, of familiar creatures.
Animal breeders reinforced particular traits to induce changes carried down through the generations – stalwart bulldogs, athletic greyhounds, ladies’ lapdogs. Geological data was also accumulating: seashells on mountain peaks, earthquakes, strata lacking fossil remains – and the most sensible resolution for such puzzles was to stretch out the age of the Earth and assume that it is constantly altering.
Charles Darwin thought deeply about why populations of animals changed in the particular way that they did. Erasmus Darwin did not. He declaimed “Everything from shells!” and resumed writing terrible poetry. Like:
IMMORTAL LOVE! who ere the morn of Time,
On wings outstretch’d, o’er Chaos hung sublime;
Warm’d into life the bursting egg of Night,
And gave young Nature to admiring Light!
Erasmus Darwin didn’t develop the theory of evolution. You could call him an abolitionist, maybe, but he was a pretty half-hearted one, if that. By the standards of his time, he was a feminist. By our standards, he was not.
He seems like a nice enough fellow, though. As a doctor, he treated his patients well. And he constantly celebrated the achievements of his friends.
Patricia Fara writes that,
After several years of immersion in [Erasmus] Darwin’s writing, I still have a low opinion of his poetic skills. On the other hand, I have come to admire his passionate commitment to making the world a better place.
And, who knows? If Erasmus Darwin was alive today, maybe he would be a polyamorist. Who’s to say what secret desires lay hidden in a long-dead person’s soul?
But did Darwin, during his own lifetime, advocate for free love? Nope. He did not. No matter what his political opponents – or our own era’s oblivious scientists – would have you believe.
Header image from the Melbourne Museum. Taken by Ruth Ellison on Flickr.