Evolution
The subject of Evolution keeps coming up in discussion between scientists and religious devotees and there have been some repeated misconceptions that really have all been answered many times in the past but continue to be ignored or misunderstood. This is just a few of my ideas and ways to think about the answers to these questions in case it makes any improvement to the debate.
What is evolution?
To give it it’s full name, it is “The theory of evolution by natural selection” … a natural process by which the complex variety of life that we see around us has been formed. Nothing guides this process except the simple fight for life – competition between individuals for resources to live and the chance to breed and pass on their successful traits to their next generations. Individuals who are not so well adapted die without reproducing and so their traits are slowly filtered out of successive generations.
When Darwin & Wallace jointly proposed the theory they took years to think of ways to prove and explain how this might occur but they didn’t know of the precise mechanism that might be driving this process. But today we know about DNA and how it is the building block of life within our cells and how subtle mutations and changes to the complex DNA mollecules happens during reproduction and other natural processes.
If humans evolved from monkeys then why do monkeys still exist?
Basically, because Evolution isn’t a process that just creates the most intelligent life form on the planet as its ultimate purpose. Evolution fills the world with a web of life where each species is adapted to an ecological nice, which itself is one of billions of slightly different niches around the world.
Consider humans – we all have a family tree which describes how we are related to our ancestors. As we look further back we encounter branches coming in from other parts of the family, or famileis related by marriage. Further back still you would discover more and more branches joining which show how you are distantly related to other entire branches of society, but still all humans.
But if you could go way further back, before human history started – remembering that written human history is only really a few thousand years old. Go back to pre-history – to your ancestors that lived after the last ice age, possibly alongside other species of hominid (human-like animals). Now you would potentially see that the humans back then looked a bit different to us – not just in their clothing either – in the subtle structure of their faces and the shape of their skulls. This is still one of your ancestors but you can see it is also an ancestor of a lot of other humans too. Going further back you might see that earlier ancestors looked a bit more like monkeys – hairier and sometimes moving on all fours – these might be shared ancestors with other apes or monkeys if we go back far enough.
Over humndreds of millions of years we would have traversed millions of generations in your family tree and found ancestors that are shared with not just monkeys but other mammals too. This is just a way to visualise how your ancestors are shared not just by people in your family but much further back by ancestors of the monkeys or the dogs and cats we see today. Each animal or plant alive today is at the tip of their family/ancestry tree and is suited to the niche they occupy in the web of life, all coexisting and yet all sharing ancestors back in time.
Isn’t it just a theory?
This is a very basic misunderstanding of the word “theory” because in common parlance it means an idea that has been proposed but which is possibly unproven or uncertain. But in science a theory/theorum is considered to be the truth – or the currently accepted explanation for a phenomenon. It isn’t unproven or vague – it’s what the scientific community consider to be fact.
Now, that isn’t to say that it will always remain the best explanation because science itself evolves as we learn more about the world around us and we invest new tools and ways of examining the world. DNA is a good example where Darwin had no idea that it existed but if he had known about it and its vital part in the inherritance of traits then he would have been overjoyed because it rounds off his theory nicely.
I don’t believe in evolution!
Well, that’s not a problem because scientific truths exist without the need for belief – they are understood to be true and proven beyond any reasonable doubt without the belief of anyone. On the other hand if everyone stopped believing in gods they would vanish over hight – they only exist in the minds of their devotees.
To elaborate, when a scientist has an idea this is written down as a hypothesis – an untested or unproven proposal based on logic or experience of an observer. This is really where religions stop because they have a lot of stories and ideas but they have no facts to back them up – just conjecture. Scientists on the other hand take it a step forward and work out ways that they can test their hypothesis in the real world. So if they are right then what would the world look like? How could they ru nan experiment that would test their idea? They perform the experiment and if it returns results in the real world that support the hypothesis then the scientist might publish their idea (along with all the details of how they tested it experimentally and their findings) in a scientific journal for their peers to read and understand. Then other scientists will take that information and run their own experiments on it to see if they reach the same results and their findings will be published and go into the melting pot of debate.
A hypothesis only becomes accepted by the scientific community as a theorum when it has been independently tested and an expert concensus has been achieved.
How can evolution create something as complex as the human eye?
Actually this was explained back in the very early days because we have examples of species that show every stage in the evolution of the eye, from light receptive cells on the skin surface through the development of light-sensing organelles and then the development of a lens and the means to focus it. It just takes time and a pressure to evolve and become better adapted to survive, and actually eyes are very useful and give significant advantages for survival if an individual is placed in a life threatening ecosystem where detecting food or a predator could mean life (and the passing on of their traits) or death (and the loss of their traits).
Why are belief and understanding different?
This is an interesting question because in a free society we are all free to have our own beliefs and often this is misunderstood as meaning that beliefs are equivalent to truths, but they’re not and I’ll explain why.
Simply put, the truth is possibly the most important thing that any of us should aspire to. Truth enables us to know and trust with a high degree of certainty what the outcome of critical actions might be. We know when the train will arrive because we know the distance it will travel and the speed it will be going – we have the ability to predict very accurately. Likewise we can predict the movements of distance planets so accurately that we can land a human on them at a precise location, allowing for their orbits and rotation. We don’t just believe that we will get there – we know it because we have proven the science and we trust our understanding of it.
Similarly, Eratosthenes also didn’t just believe that the Earth was round, he used science and mathematics to prove it. He had heard that in the neighbouring city of Syene there was a deep well, where at noon on a particular day of the year the sun shone vertically down it. He hypothesised that if the Earth was round then if he measured the shadow cast by a vertical rod of known height at noon in Alexandria at the same moment that the sun was shining down the well in Syene then, knowing the distance between the 2 cities, he would have enough information not just to prove that the Earth was round but also to calculate it’s circumferance. If the Earth was flat then at noon on that day there would be no shadow cast by the rod because the sun would also be directly above it, but if the Earth was round then a shadow would be cast and by using simple geometry he would know the angle between the well and rod which when combined with the distance between the cities would give the circumferance of the sphere. This was a huge leap forward in understanding the nature of our planet and remarkably, even given his limited equipment, he was between 1-2% out.
The truth also might not be as simple as 1+1=2 and it might just tell us a likely outcome from a complex situation. We understand better and better what controls and governs the weather but it is still a complex system that we cannot be 100% sure about. But if you want to know if you can have a barbecue on Saturday then we still rely on the most trusted source of truth – weather experts who predict this kind of thing using science.
Similarly, we build aircraft out of components that we have tested and from materials that we understand the nature of through science. We don’t just trust to faith and belief in a material or a design when lives depend on it. We have hundreds of years of experiment and testign to understand how materials and designs behave under stress and so we can put out trust in the airplane knowing that science is underpinning every aspect of the manufacture. We actually had a tragic demonstration where an inventor’s faith or belief in their creation went against scientific prudence and facts, when the Titan submersible imploded in 2023 killing all 5 people onboard. Experts with decades of materials research and experimental evidence behind them had been warning the company that the design was unsafe but the maverik owner had such faith in his design that he dismissed all of these concerns and went ahead anyway. Another failure of pride and ego over cold, hard science.
In all situations, when lives are at stake or there is big money riding on an outcome then successful people will always go to a source of truth rather than a belief system.
