Exploring the nature of science through courage and purpose: a case study of Charles Darwin’s way of knowing

The courage of conviction

While several qualities pertain to human endeavor, such as persistence, creativity, reason and logic (NGSS 2013), there is an additional quality that pertains to Darwin, and that is courage. While this may not be obvious yet, Darwin recognized, long before his thoughts on evolution were ready, that dangers may arise during and after its publication. Darwin foresaw dangers in many places, including his marriage, which greatly worried him. It was one thing to publish for an audience many of whom he would never meet, it was quite another to think of publishing a manuscript his wife would find difficult to accept because of her devout adherence to religion.

Darwin was convinced of his solution to evolution’s puzzles long before he married his cousin, Emma Wedgwood. The question then was whether or not to tell her, and his father advised Darwin to conceal his feelings, but his anxieties grew, “not because he thought he was wrong about the origin of species, but because he felt sure he was right. He knew what he had to say would be shocking to Emma and others who believed God were the creator of all species,” (Heiligman 2009).

Despite this deep religious rift, Charles and Emma believed unfailingly in the deep-seated goodness of the other. Even as Charles pursued thoughts that could well brand him, and by association, his family as non-believers, they trusted each other. In fact, if Darwin had published his explanations of evolution in an earlier century, he may well have been called a heretic, and subject to the Inquisition. To advance his ideas on evolution it seemed he must wage a private battle between the religious convictions of the day and the implications of his theory. This was a fight he ultimately accepted, one requiring the greatest courage for over 20 years, beginning from his engagement to Emma.

Summary and extension

Darwin’s early endeavors are seen very much as outgrowths of the naturalism that surrounded him. His ardent pursuit of nature became a mixture of experiential and academic knowledge rooted in the wisdom of the time, but wisdom which it did not take Darwin long to surpass. Extension: How did the era of the explorer-naturalist help Darwin’s endeavors to learn, even while doing poorly in his academic classes? Could such an approach, which is, substituting field work experience for the academic classroom, work today as it did for Darwin?

Summary and extension

Through experiences in collecting and classifying, Darwin came to understand the patterns of nature, and how important they are for establishing relations among species. Extension: How did Darwin’s beetle collecting and observations made with Sedgwick help him understand the importance “of order in nature”? How in fact did that occur?

Securing passage

Darwin’s place aboard ship was not earned from years of professional study, but rather from good fortune, recommendations from his mentors, and the fact that others had already turned down the invitation. While Darwin’s greatest insights and theories came long after the voyage, it provided a most important opportunity and Darwin was quick to see how such a voyage would expand his way of knowing. The process leading to his selection as ship’s naturalist demonstrates Darwin’s immediate pursuit of such an opportunity, even though there would be numerous obstacles to face in gaining approval. Here was a chance to pursue earlier dreams of exploring the tropical world, but to do so required him pursuing each of many steps needed to secure passage.

The remarkable opportunity to serve aboard ship as a naturalist and companion for the HMS Beagle’s Captain, Robert FitzRoy, began with a letter from Steven Henslow informing Darwin of the Admiralty’s interest in securing a qualified individual to serve aboard the Beagle. Upon seeking his father’s approval, Doctor Robert Darwin made it clear that he would never allow his son to depart on such a dangerous voyage, especially one offering no future employment.

However, Darwin’s Uncle, Josiah Wedgwood, was willing to speak to Darwin’s father on the matter, and succeeded in convincing Darwin’s father to put aside his reluctance, and grant his son this opportunity. This was no little commitment, for aside from being concerned with his son’s safety, Robert Darwin had to finance his son’s passage for a five-year mission. At that moment, Darwin’s fate had depended upon his Uncle’s willingness to travel to the family home in Shrewsbury and confront this mighty man on behalf of his son. If Uncle Josiah had failed to persuade the Doctor, his son would have never been aboard ship when it sailed.

As Darwin later recorded, “The voyage of the Beagle has been by far the most important event in my life, and has determined my whole career; yet it depended on so small a circumstance as my uncle offering to drive me thirty miles to Shrewsbury, which few uncles would have done, and on such a trifle as the shape of my nose.” (Darwin 1958).

Upon gaining his father’s approval, Darwin’s next challenge was to have an interview with Captain FitzRoy and seek his approval. In addition to being an able seaman, FitzRoy was a self-made expert in phrenology, using observations of the skull’s shape to indicate strengths or weakness of different faculties. As their interview ended, the Captain reflected on Darwin’s facial features. He thought they indicated a lack of resolution. The Captain “… doubted whether anyone with my nose could possess sufficient energy and determination for the voyage (Browne 1995).

However, FitzRoy recanted, and finally his place onboard was secured with the support of his father, and the approval of the Admiralty. Darwin’s eagerness and lack of other concerns led to an adventure that others were unable to pursue, and that would change his life and scientific career forever.

Way of knowing

When the HMS Beagle left England in 1831, its primary mission was to chart the South American coastline. Darwin’s appointment as the ship’s naturalist enabled his study and observation of all things natural wherever ship dropped anchor. This included geological formations, coral reefs, living species, fossils, and the people and cultures he encountered. Like other naturalists of his time (Hemming 2015), the social and local knowledge accumulated for each species collected expanded their way of thiking. Summarily, Darwin’s experiences with diverse cultures opened another avenue of learning, with recollections of extreme anger and disgust over slavery, understanding the use of species in local diets, and picking up on observations he missed, but obtained from local citizens.

Darwin brought books aboard ship containing the most recent knowledge of geology, exploration, and observations of the dense, tropical forests he would encounter. These books, along with those of the Beagle’s library, helped build a foundation for considering nature’s diversity, his collecting experiences, and as he began to theorize on all that he was finding. As his confidence grew, he found himself able to “refine, elaborate, revise, and extend this knowledge,” (NGSS 2013). Darwin’s observations guided him to new theories which were astounding at the time, and have remained influential to the present day. As such, the voyage led to a way of knowing that surpassed what he could have accomplished if he had remained in England. The following examples illustrate this fact.

Fossil mammals

Imagine you were cast back in time to a land of giant mammals stretched across the southeastern shores of South America. Then, you were rushed forward to the year of Darwin’s excursions in 1833. Now, all you could find were smaller, diminutive forms of the giants you saw previously. Some of Darwin’s most remarkable discoveries were the fossil remains of those giant mammals. As he would remark, “The most important result of this discovery, is the confirmation of the law that existing animals have a close relation in form with extinct species,” (Darwin 1839).

Using this new understanding, Darwin was able to “refine and revise” the state of knowledge for these towering animals. For example, he could relate the nine feet long fossilized form of a Toxodon to the living form of the capybara, the Megatherium to the three-toed sloth, and the Macrauchenia to the ever present guanaco. From these specimens, Darwin realized that fossils of extinct animals can closely resemble living species within the same geographical region and that modern forms can be derived from those of long ago.

Fauna of the Galápagos Islands

In the fall of 1835, the Beagle sailed to and around the Galápagos Islands. After visiting four islands, Darwin observed that native to each one were tortoises, mockingbirds, and the finches. He established similarities in climate and geologic formation among the islands, and yet, noticed that they supported animals of close relation, but differing substantially in structure and eating habits.

Darwin encountered finch populations on the islands, but most species collected came from two islands: Charles (Floreana) and James (Santiago) (Sulloway 1982a, b). However, while collecting these birds, Darwin neglected to tag each finch by island, perhaps due to his enthusiasm for the moment. While Darwin was well versed in labelling coleopterans, he was still far more familiar with geology. Consequently, most of his time was spent “geologizing” on the Galápagos, not as a well-trained ornithologist. Upon return to the Beagle, he did his best to classify the birds, mistakenly identifying them as finches, warblers, American blackbirds, wrens and grosbeaks.

Summary and extension

Aboard the Beagle, Darwin’s opportunities for learning increased dramatically. Two particular examples of how Darwin learned from his experiences were given: unearthing fossils from South America and encounters with animals on the Galápagos Islands. Extension: Compare and contrast these two examples of what Darwin learned and the type of knowledge gained that would later to advance his theories evolution.

Coral reef formation

The Beagle reached the Keeling Islands in April of 1836. In his Principles of Geology, George Lyell adopted a view that coral reefs formed from the tops of submerged volcanoes, allowing the living polyps to grow in the upper reaches only, and rim the creator with coral. However, Darwin had deduced a different view, one relying on subsidence of ocean floor, in conjunction with the elevation of the lands of South America. Such things were in accordance with Lyell’s “compensatory change” in the earth’s crust.

If Darwin’s view was correct, then “coral should be hundreds of meters deep, having grown steadily as its mountain foundation subsided,” (Huxley 2007). Captain FitzRoy arranged for his crew to dredge the bottom of the coral, and indeed, the great expanse of hidden coral was revealed, proving Darwin’s hypothesis to be correct, thus revising the explanation as set forth by Lyell. Darwin was able to show an “inch by inch” approach to the growth of the coral, accumulating great height as the land below subsided (Browne 1995). Thus, Darwin’s studies were able to benefit from, and link, biological evidence and geological structure, laying the basis for modern theories on reef formation and replace Lyell’s earlier theory.

Re-classifying the Galápagos finches

Upon return to England, Darwin realized that by neglecting the island location from which each bird was collected, he hindered its correct classification. Darwin needed help to clear up this confusion. Fortunately, other members of the crew were willing to provide Darwin with their collections of similar birds, but with each one identified by its respective island. However, finding someone suitable to help with this classification was difficult. He found “… the geologists all willing to render all assistance and exceedingly kind, but the Zoologists seem to think a number of undescribed creatures rather a nuisance,” (Browne 1995).

Darwin was relieved when scientists at the Zoological Society of London presented the birds to John Gould for classification. Eventually, Gould’s painstaking work revealed these “undescribed creatures” from the Galápagos to be 13 species of closely related birds, quite unlike Darwin’s tentative classification as unrelated birds. Their form was so peculiar that Gould placed them in an entirely new group, classified as 13 species, divided among 5 genera.

Within 6 days after receiving them, Gould presented the Galápagos finches as new to science. He deciphered the significance of the graduated differences among beak size. This separated him from other ornithologists of the day by noting that this variability in beak size among the finches was contrary to beak size being one of the most stable family characteristics. Usually, the plumage was highly modified and variable, whereas in the finches, coloration was almost identical (Sulloway 1982a).

In the first edition of Darwin’s Journal of Researches (Darwin 1839), in contrast to its second edition (1845, Darwin gave virtually no attention to the finches. While Gould deserves the credit for unravelling the mystery of the finches, Darwin deserved credit for his continued questioning of the significance of the Galápagos animals as examples of a species’ change over time, which he summarized in the second edition of his records aboard the Beagle as: “The most curious fact is the perfect gradation in the size of the beaks in the different species of Geospiza, from one as large as that of a hawkfinch to that of a chaffinch…there are no less than six species with insensibly graduated beaks…Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends,” (Darwin 1845).

Summary and extension

This theme contains one of the key truths of the nature of science: all data, publications, research, are to be made available for review and revision. The following questions consider this vital point. Extension. Why did Gould’s final classification of the Galápagos finches assume much greater importance than Darwin’s classification of the birds while at sea? How do you think Darwin felt after advancing his theory on the formation of coral reefs, which surpassed and replaced the theory of such laid out by Charles Lyell, his close fined and mentor?

The origin of species

Theories are explanations for observable phenomena, based on a body of evidence developed over time. By the time Darwin was ready to publish, he had provided a theory for evolution working through natural selection. Darwin was not the only person to arrive at such a theory, as working independently and in another corner of the globe, Wallace (1858) produced such a theory as well. It was indeed remarkable that from both men came to a similar if not equivalent idea—that evolution, meaning change over time, occurred through natural selection.

It was this idea, among many others, that Darwin put forward in his book, On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life. Some 25 years in its conception, the book provides a foundation for evolutionary biology. It removes evolution from prior ignorance, by presenting a scientific theory which allows populations to change over generations, and frees them from the bonds of immutability, as professed by the Church of England. In addition, Darwin proclaimed that the diversity of life arose by common descent with modification allowing for changes in species over time.

All of Darwin’s observations and insights, plus reading of increasing population growth and demand for limited resources, brought him to his theory of natural selection. Briefly, this means that individuals better adapted to their environment survive and increase in number through reproduction. It relies on four propositions which again Darwin had seen or studied. First, living organisms reproduce at rates exceeding their survival. Second, members of a species show variation among individuals, variations which are the basis for beneficial adaptations. Third, there will be competition among members of a species for available resources, and fourth, selection will occur, with the most well adapted surviving.

Darwin explained natural selection in the Origin (1859) as, “any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, …, will tend to the preservation of that individual, and will generally be inherited by its offspring.” In concluding this book, he states, “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved,” (Darwin 1859).