On February 12, 1809, two babies were born on opposite sides of the Atlantic Ocean. Both were destined to change the course of human history. One was Abraham Lincoln and the other, Charles Darwin. Both, in some small way, owed a part of their ultimate success to the writings of Dr. Benjamin Franklin.
What would Ben Franklin say about the accomplishments of these two great men? Let’s consider Charles Darwin in this blog and Abraham Lincoln in the next.
Franklin knew both of Charles Darwin’s grandfathers. Dr. Erasmus Darwin was one of the great intellectuals of his age. Indeed, had he not been overshadowed by his illustrious grandson, Erasmus would be the Darwin we speak of today. As both a physician and a poet, Erasmus Darwin made his mark. His massive four-volume poem Zoonomia acknowledged the evolution of species but offers a wrongheaded explanation of the process.
By Franklin’s time, most men of learning accepted the idea that the species were not fixed but did, instead, change with time. They knew this from the fossils found in successive layers of rocks. The mechanism proposed by Erasmus Darwin and his colleagues suggested that acquired changes in an organism could be passed on to the next generation. If an animal, such as an antelope, needed a longer neck to reach higher leaves on a tree, the animal would will his or her neck to be a bit longer and transmit this change to their offspring.
Franklin also knew Charles Darwin’s maternal grandfather, Josiah Wedgwood. The great potter created a beautiful white-on-blue porcelain piece featuring a profile of Benjamin Franklin to honor his famous friend.
Charles Darwin did not learn about evolution by sitting on his grandpa’s knee. Erasmus died several years before Charles was born. Instead, Charles was sent to college to become a physician like his grandfather and father before him. The medical profession, however, didn’t hold the young man’s interest. Luckily, Charles was selected to work as a naturalist on a multiyear voyage of the HMS Beagle, a trip that would ultimately change the trajectory of human knowledge.
I need not review here the conclusions of Charles Darwin about the process of evolution. Instead, I’ll describe how Darwin did what he did. After returning from his voyage on the Beagle, Darwin was convinced that evolution was the fact, but he didn’t understand the mechanism whereby species would change over time. He therefore took the critically important step of joining a pigeon fancier’s club and spent many hours talking to breeders about how they introduce changes in successive generations of animals. Every breeder knows that there exists within every litter random variation among littermates. The breeder selects as parents for the next generation those animals with favored traits. In this way, animals change over time.
Who or what, Darwin wondered, served as the breeder in nature? In his autobiography, Darwin explained how he came to the answer. He had been reading the works of Robert Malthus, a Protestant minister, who wrote a book on population. Malthus, using rectory statistics from English parishes, stated that populations increase faster than food supplies. Thus, there was always a competition for food among the members of a generation. Darwin took this idea and realized that nature itself acted as a selective breeder by producing more organisms in every generation than could be sustained by the available resources. The natural variation between each member of every generation, whether plants or animals, would mean that some are more fit to survive in a challenging environment than are their siblings and cousins. Those favorable traits that allow this to happen are then passed on to the next generation.
Thereafter, Darwin always credited Malthus with providing the vital clue to unlocking the secret of nature’s great mechanism for allowing succeeding generations of life to adapt to an ever-changing environment.
And where did Malthus get his ideas? The parson, it turns out, had read the writings of Benjamin Franklin whom, in 1751, produced a pamphlet designed to convince Great Britain that it should do everything it can to acquire (or snatch) the central part of North America from the French. In describing the way the continent would gradually become populated, Franklin offered a concept we today call “population dynamics.” He wrote, “there is no bound to the prolific nature of plants or animals but what is made by their crowding and interfering with each others’ means of subsistence.”
This is simply another way of stating Darwin’s conclusion that overpopulation and the struggle for resources have an impact on survival.
Franklin, of course, was not concerned with the evolution of species nor, for that matter, did he ever say anything about that particular subject. Nevertheless, were Franklin to return today in time to witness the celebrations honoring the 200th anniversary of Charles Darwin’s birth and 150th anniversary of the publication of his seminal masterwork, On The Origin of Species, he would no doubt feel a sense of pride in the role his own writings played in the evolution of Darwin’s thinking.