When Charles Darwin first presented his theory of natural selection, naturalists everywhere kicked themselves.
Though many were undoubtedly delighted with its profound implications, others would have cursed the air bitterly as the theory clicked into place in their minds: it was so obvious! It all made such perfect sense – how had I not seen it myself?
And yet no one had seen it.
Even today, with the benefit of almost two hundred years of accumulated evidence and thought concerning the theory of natural selection, it still continues to elude many people – including those with substantial exposure to biology as a scientific discipline.
Even among students with at least two years of formal education in biology, no more than 31% are able to demonstrate a true understanding of the theory.
So what gives?
Why did it take us so long to discover the theory – which appears to be no more conceptually difficult than the notion of gravity – discovered a century earlier?
And why do we continue to misunderstand it? Are these two sides of the same coin; is natural selection just an inherently difficult concept to grasp?
In this article, we’ll see that it was no miracle that the theory evaded discovery for so long. Natural selection dons a deceptive disguise, shielding it from the prying eyes of would-be discoverers. And even after that disguise has been removed, the theory doesn’t readily reveal itself – as evinced by our continued misunderstanding today.
I’m certainly not alone in thinking that ‘Evolution by Natural Selection’ is the most elegant theory ever propounded.
A truly good theory should pack a heavy explanatory punch from relatively simple assumptions. That is, it should give us a lot from a little – kind of like a thrifty miser who spends little money but somehow accumulates a wealth of possessions.
Darwin’s theory was as thrifty as they come, explaining the complex diversity of life itself, from the wonky march of ants to the ponderous plodding of elephants. And all it was required to spend to acquire these riches was a few relatively simple principles – namely, high fidelity but imperfect replication (replication with occasional mutations), and a tendency for the best replicators to predominate in future populations – simply as a trivial result of statistical processes.
Once understood, the theory of natural selection seems so simple – and obvious.
Yet for the two and half millennia since the Greek philosophers introduced a naturalistic lens through which the world could be viewed; where all things were thought to have reasonable, mechanistic explanations; where the world was known to be built from matter and maths – not a single thinker had alighted on the quintessentially mechanistic explanation for life itself.
And yet it was sitting there all along, waiting to be plucked by the first mind fortunate enough to stumble into its path. Knowledge of DNA or biochemistry was not prerequisite – Darwin himself lived in a time before DNA had been conceived, and in which biochemistry had barely sprouted as a field of knowledge.
So why did it take so long? You would think that among all of those brilliant philosophical and scientific minds in the preceding two millennia, someone would have cottoned on.
After all, atoms had been dreamed up in the time of the greeks, and even the revolutionary, abstract concept of gravity was discovered a century before natural selection.
The reason for its elusiveness, I believe, lies primarily in a cunning deception – a masterful conjuring illusion cast by the mechanistic process of natural selection itself, which fooled everyone, and prevented all from glimpsing its true nature.
The illusion was this: that every life form had been designed.
Now, to be sure, one might quite rightly assert that the products of natural selection were designed, since their myriad remarkable features – wings and teeth and hands – had been sculpted to fit some design function: to fly or to eat or to climb.
But I have used the term illusion in the following sense – namely, that something is illusory when it turns out to have a different nature than had been originally assumed.
For example, a desert mirage appears to the delirious traveler to be a real object out there in the distance, when in fact it is a trick of the heat haze and the mind.
But he really did see the thing; it actually existed – it just wasn’t what he thought it was.
The same goes with the designs of natural selection – they were illusory because they weren’t what people had assumed they were: designed by some intelligent designer.
Before the principle of natural selection was discovered, it was considered trivial that design always implied a designer. After all, humans were themselves designers, and whenever they came across some kind of unnatural craft; a building or a weapon – it was obvious that another person must have made it.
So for instance, when one considered how perfectly sculpted was a sharks sleek, aerodynamic body for gliding through water at tremendous speeds, or its razor rows of teeth for shearing the flesh of its prey – it was patently obvious that these features must have been designed, and that therefore there must have been a designer.
And there was nothing parochial about this reasoning – it was all perfectly logical. In fact, if you didn’t know about evolution, then you would have to have been something of a moron not to grant the existence of some kind of Cosmic Designer, or god.
Sure, many intelligent thinkers rejected the dogmatic assertions of the ‘pop’ gods – with all of their puritanical or tyrannical trappings – but I suspect that not many could truly abandon the idea of a prime mover; some kind of intelligent being that had lovingly crafted the earth and all of its inhabitants, even if he simply up and left after he was done.
Thus there was this persistent blind spot in our thinking – a stark shadow cast by the almost tautologically obvious assumption that design requires a designer.
This assumption was so firmly ingrained, and so obviously true – as true as one plus one equals two – that even after Darwin published his “On the Origin of Species”, many refused to accept it.
A quote by Robert Mackenzie Beverley, one of Darwin’s 19th century critics, perfectly encapsulates the strength of this conviction:
“In order to make a perfect and beautiful machine, it is not requisite to know how to make it”, he says sarcastically, with the statement intended to highlight the absurdity of what Darwin, by a “strange inversion of reasoning”, was claiming.
“[Darwin] seems to think Absolute Ignorance fully qualified to take the place of Absolute Wisdom in all of the achievements of creative skill.”
And he was right, as noted by the philosopher Daniel Dennett: the theory of natural selection is a strange inversion of reasoning; it is the refutation of an apparently logically sound premise, which is not something smart thinkers are prone to attempt.
So then, this unchallenged assumption was likely the primary impediment to the discovery of natural selection, but it wasn’t the only one – because as it turns out, every so often, a sophisticated thinker may indeed have challenged the unchallengeable.
The pre-Socratic philosopher Empedocles was one such challenger, whose theory of the origins of life featured a type of natural selection.
In his view, the separate limbs of animals were first sprouted from the earth, where they began to roam blindly in some grotesque, chaotic dance.
By chance, these limbs would occasionally converge, and swiftly combine with each other. The combinations that were feasible would survive, and those that were not – the legs of a bird on the body of a man, perhaps – would not.
Thus all of the perfect forms we see on earth could have evolved without a designer.
Aristotle too, acknowledged the possibility of design without a designer, in his refutation of Empedocles’ idea. The following quote, taken from Aristotle, Physics, Book II, Chapter 8 shows his prescient conception of evolution by natural selection – which was almost bang on the money:
“Wheresoever… all things together (that is all the parts of one whole) happened like as if they were made for the sake of something, these were preserved, having been appropriately constituted by an internal spontaneity, and whatsoever things were not thus constituted, perished, and still perish.”
But Aristotle then rejects this possibility, reflecting that embryonic development doesn’t have this random characteristic; a fetus emerges invariably with all the parts of the whole, in their proper form, and never as some random assortment of limbs.
The right thinking tools
Aristotle demonstrated that the mere germ of the idea of natural selection alone was insufficient; it would not necessarily sprout into a fully-fledged theory through sheer logical deduction. It was also requisite to possess some additional evidence, which the likes of Charles Darwin, and Alfred Russel Wallace (who conceived of natural selection around the same time as Darwin) were privy to.
Darwin and Wallace were both naturalists, each having been exposed to an extensive array of accumulated specimens of wildlife fossils documented in books, museums and private collections, and each having conducted his own research into, and observation of nature.
They had both observed that significant differences of traits within a species were possible – such as the Galapagos island finches with their variegated beak shapes and sizes – which gave the lie to Aristotle’s assumption that “[all natural things] either invariably or normally come about in a given way”.
An additional thinking tool was also instrumental in leading to the conception of natural selection: the idea of gradualism – which holds that something may change over time via the accumulation of many minute changes.
Darwin was well aware of this phenomenon in the context of geology, where, over an immense geological span of time, a mountain could be thrust into the heavens little by little, or an edifice of intricately shaped rocks could be sculpted by eons of erosion.
This appreciation for unthinkable periods of time, and of the potential for monumental changes to be built gradually from infinitesimal ones, was probably implicitly understood by both Darwin and Wallace, and so would have been woven into their thinking about the origin of species.
But what of the ‘Design assumption’ – why did that not serve as a pitfall for Darwin, as it had for countless thinkers before him?
Well, it is not the case that Darwin and Wallace were a pair of anomalous thinkers, who alone pioneered a movement away from creationism, towards a naturalistic explanation for life forms. Rather, they formed a part of the immense, rising swell of the age of enlightenment, in which theological theories of the universe slowly began to falter in the light of new evidence and more convincing scientific alternatives.
A new paradigm had been precipitated by the enlightenment, and was responsible for a growing movement to question established truths – among them, the design assumption.
In fact, many pre-Darwinian theories emerged during this period, involving the ‘transmutation’ of species over time – so the idea of evolution was nothing new.
But even amid these attempts, natural selection avoided detection by so many for so long.
Is Natural Selection just difficult to grasp?
Among all of these naturalist scholars, many of whom had shirked the design assumption, and were aware of concepts like gradual change and geological time, only two of them alighted on the right idea.
Perhaps the theory is simply difficult for us to wrap our heads around.
There is a host of data to suggest that an unprecedented degree of misunderstanding of natural selection exists among the general public .
Even among students with two or more years of biology under their belt, remarkably, no more than 31% could demonstrate a scientific understanding of the process .
Instead, students viewed evolution as more of a ‘Lamarckian’ process, named after a theory put forward by Jean-Baptiste Lamarck around the time of Darwin, to describe the origin of species.
In this conception, an animal makes adaptations in real time during its life, and then passes these changes to its offspring.
Lamarck uses the example of the evolution of the giraffe’s long neck. He envisioned that a giraffe would stretch its neck as far as possible to reach higher leaves, and in doing so, would stimulate a physiological change to cause the neck to grow. This change would then be passed to its progeny, who in turn could exaggerate the trait further, by the same mechanism.
When thinking about evolution, people tend to intuit this same mechanism – indeed, I can recall that in my own benighted youth this is how I imagined evolution to work.
I think this is because we can more easily imagine the Lamarckian process, since we are already implicitly used to the concept. We are well acquainted with the process of learning, where new capacities are acquired, and then can be passed on to subsequent generations.
Furthermore, we can readily envision Lamarckian evolution taking place – we can quite easily see, and feel, the giraffe stretching out his neck. We can imagine this change being permanent, and then passing to the offspring.
In contrast, natural selection is a much more abstract concept. There is no easy way to envision the whole process; to hold it in our minds as a complete, cohesive picture where we see all the moving parts, as well as the gestalt effects.
Rather, we need to mentally cycle through the premises and the consequences, every time we wish to ‘see’ it.
The abstract nature of natural selection thus places it out of reach of lazy thought – along with mathematics, and quantum physics. In order to understand it, one must strain their mind to do so.
So it turns out there were a number of impediments blocking the discovery of natural selection.
In the first place, it required a person who was used to thinking in an abstract manner, since natural selection is a veritable archetype of the abstractness of science. This prerequisite narrowed the pool of contenders for the discovery down to only the most sophisticated scholars.
Then there was the design assumption – an almost inescapable quagmire of thought that imprisoned hordes of intellectuals for millennia, preventing them from even entertaining such a radical idea.
And even if someone could think effectively in the abstract, and did question the design assumption – like Empedocles, or Aristotle – there were additional prerequisites, such as an exposure to certain evidence, and the possession of certain thinking tools.
For someone to possess this curious combination of quirks was really a matter of probability. And it was only in the 18th century – where animal specimens and naturalistic evidence abounded, and intellectuals everywhere were in the habit of questioning the status quo – that this probability started to claw its way away from zero.
But even following its discovery, the abstract, conceptual difficulty of the theory remains.
Though the theory seems simple once we truly understand it, the fact that it lay undiscovered for millennia should remind us that this is by no means the case.