It’s one of the great ironies of Charles Darwin’s life that he was perhaps his own best evidence. In the physical sense, evolution works not through environment but through heredity. The environment may create circumstances through which certain traits are more fit to survive, but no environment can create the correct circumstances to bring out traits within a living organism that the organism did not inherit.
Darwin himself was born in extremely propitious circumstances to an exceedingly wealthy family, thereby allowing him the leisure and equipment he required to fully explore the depth of his genius. But had he not been born to a family that positively teemed with geniuses, he would never have had such raw intelligence to develop.
Relatives of his included Ralph Vaughan Williams, one of England’s greatest composers, Francis Galton, the father of Eugenics, and ten other members of the Royal Society - England’s eternal club for their most distinguished scientific minds. His father, Robert Darwin, was one of the pre-eminent physicians and surgeons in England, and advanced theories not unlike what would later be known as psychiatry. His maternal grandfather, Josiah Wedgewood, was one of the first great captains of British industry, whose innovations in pottery production did much to create modern assembly line manufacturing. His paternal grandfather, Erasmus Darwin, is an extremely important biologist (or naturalist, as the field’s practitioners were then called) in his own right, nearly discovering through plant life what Charles would discover from animal life two generations later. But whereas Charles was ultimately a scientific monoglot, whose achievements were “limited” to a genius for perceiving the natural world and a talent for writing prose, Erasmus was every inch a charismatic polymath whose other achievements included numerous inventions, pedagogy, and poetry.
And yet it was by no means a given that Darwin would follow in the footsteps of his distinguished lineage, let alone surpass it exponentially. As a young man, he dropped out both of medical school and of divinity school. Unlike his multi-faceted and extremely charismatic grandfather, Darwin clearly suffered from mental ailments which today would probably be termed a learning disability and an anxiety disorder. All through his youth, Darwin displayed terrible difficulty learning anatomy, mathematics, and foreign languages. He would later become a very well-liked man, modest and gregarious, and by all accounts a wonderful father to his many children - yet his letters are not without their anguished worries and flashes of temper. As Paul Johnson points out, all these defects cost him terribly. Whereas his grandfather came reasonably close to the discovery of genetics, such a concept to explain hereditery survival never occurred to Darwin. Without the understanding of human anatomy or the mathematical components of molecules, how could it? And without a rudimentary knowledge of foreign languages, he never could have come across Gregor Mendel’s 1866 paper on genetics, even though German - the mothertongue of Prince Albert - was the most common foreign language learned in Victorian England.
Nevertheless, Darwin was an agreeable and charming young man, and many of his teachers saw the potential of such a brilliant but wayward student. For all his obvious flaws, he still was considered an extremely capable youth in search of a niche - a niche his father worried he would never find. “You care for nothing but shooting, dogs, and rat-catching,” his father once accused him, “and you will be a disgrace to yourself and all your family.” And yet it was these frivolous talents - the observation of dog-breeding, the taxing physical labor of hunting and marksmanship, the patience of animal dissection, which gave him the perspicacity and endurance to create enormous troves of observation every day.
This niche came in the form of the HMS Beagle, a ship charged with measuring the sailability of various seaways in South America. One of Darwin’s professors recommended him for a job as the ship naturalist, and Darwin was all too happy to comply. The work itself was horrible drudgery that seemed to breed demoralization. The first captain of the Beagle killed himself during the voyage, and the captain under whom Darwin worked, Robert FitzRoy, would kill himself later. FitzRoy was only too happy to format his navigation to whatever specification Darwin required so that he could collect the maximum possible specimens, it gave meaning to an otherwise meaningless-seeming voyage.
Even so, it’s almost impossible to imagine the stamina and willpower Darwin had to summon to fulfill his purpose during his five years aboard the HMS Beagle. Even though he brought a valet with him, most of the animals he had to collect took enormous effort. There must have been days upon days when he was suffering from bad food, poisonous food, lack of food, seasickness, terrible heat and cold, exhausting hikes, rude and dangerous shipmates, and psychological isolation. And yet every one of the roughly five thousand specimen Darwin collected is precisely notated with pages of observation to go along with them.