In many ways this chapter may be the hardest for me to write. That’s not because evolution is particularly complicated but because it’s so obvious. At least it is to me. But it wasn’t always like this. There was a time when I really struggled with the whole concept of evolution. Again, that wasn’t because it’s complicated – it was because I really didn’t want it to be true.
However, regardless of what I wanted to believe all those years ago, evolution is true – it is a fact as indisputable as gravity or heliocentric theory (the notion that the earth revolves around the sun and not vice versa). In fact we have more evidence for the fact of evolution than we have for the theory of gravity, heliocentric theory, or even most of what we think we know about quantum mechanics.
So why did I once find it so difficult to accept evolution? The answer to that is both simple and complicated….
I found evolution to be challenging because I was a fundamentalist, creationist Christian – a ‘young earth’ creationist at that and evolution contradicts most of what I chose to believe. That’s the simple part.
I was a fundamentalist, creationist Christian for a variety of reasons, mainly social and based upon a need to ‘belong’. That’s the complicated part.
I’m aware that some readers of this blog – some of whom are good friends of mine will find these concepts just as challenging as I once did. To those people I say this…..
I have no wish to attack you and nothing that follows is intended to offend anyone. However, this information is based upon the best available evidence, at least the best evidence available to me – evidence which I will try to introduce as this series progresses.
But first we need to say a little about the nature of evidence, how we know what is true (or at least how we make our best guesses) and how we know when something is likely to be false. This will involve a little detour before we begin talking properly about evolution and evolutionary psychology – bear with me.
By far the easiest way to test whether something is true is to see if it can predict what we might find in the real world. That’s why scientists come up with hypotheses (possible explanations for stuff) and then devise tests to see if what really happens is what we would expect according to the hypothesis. Hypothesis really means ‘an explanation with little or no supporting evidence’. The more tests the hypothesis passes the more evidence it acquires to support it until eventually it moves beyond the status of hypothesis and becomes a ‘theory’.
Hypotheses with loads and loads of supporting evidence are still technically just theories although in common language they become known as facts. That’s the situation with the theory of evolution. It’s still a theory because in science everything is only a theory – an explanation that is supported by evidence – but nothing is a fact because there’s always the chance that new evidence might arise to disprove it. In fact the bulk of scientific testing is designed to try to find conflicting evidence, to disprove theories. If no evidence can be found then the theory is accepted provisionally. But the moment evidence is found that proves it cannot be true the theory is abandoned. That’s how science works. The process of trying to find evidence to disprove a theory is known as ‘falsification’. Remember that term – it’s really important. Falsification.
It’s a bit of a paradox but we can only really know what’s true by trying to disprove stuff – trying to prove our theories are correct doesn’t work. Here’s why…
Let’s assume that I have a hypothesis – I suspect that all mammals live on the land and so I set out to prove it. I go to the internet (doesn’t everyone use the internet these days?) and I type into a search engine ‘land-dwelling mammals’. Instantly I’ll find loads of evidence confirming what I already thought and I’ll be more convinced than ever that my hypothesis is correct. I’ll elevate my hypothesis to a theory because I have the evidence to support it – even to ‘prove’ it but I’ll be wrong.
Had I typed a different search term into my computer I’d have come up with a completely different result. If I’d looked for the evidence against my hypothesis instead of just trying to confirm it I’d have a much better way to test it. What would happen if I searched for ‘sea-dwelling mammals’?
Instantly I’d have been confronted with images of whales and dolphins and my hypothesis would crumble before my eyes. I’d know that my hypothesis was incorrect and I’d have to modify it. I’d eventually end up, as most people already know, with a hypothesis that ‘most’ mammals live on land but that there are a few exceptions. Such is the power of ‘falsification’.
This idea is so powerful that a famous philosopher of science called ‘Karl Popper’ suggested that falsification is the key condition when trying to solve what he called the ‘demarcation problem’ – the difference between ‘science’ and ‘psuedoscience’ or even ‘science’ and ‘nonsense’.
‘Psuedoscience’ and ‘nonsense’ seek only to prove their claims whilst ‘science’ seeks to disprove hypotheses and theories – it seeks to ‘falsify’ claims.
That’s why scientific ideas progress. As each hypothesis or theory is disproven, scientists modify their beliefs and retest, all the time coming closer and closer to reliable truth. Psuedoscientists and nonsense merchants do the opposite – they seek only to find evidence that supports their existing beliefs and ignore or suppress ideas that contradict them. This process of looking only for supporting evidence is what researchers call ‘confirmation bias’, a tendency that scientists work hard to ‘factor out’ of their research methodologies. The confirmation bias lulls us into a false sense of security, even a false sense of competence – we believe that we were right all along and so we don’t ever try to improve upon our existing beliefs.
That’s why creationism hasn’t really changed for thousands of years whereas the theory of evolution keeps getting more and more refined and so more and more reliable. It’s because of this process of falsification. The attempts to falsify evolutionary theory mean that the overall picture is continually refined. We now talk about the ‘modern synthesis’ of evolution – a significant improvement upon Darwin’s original idea which, however brilliant it was (and make no mistake Darwin’s theory was brilliant) was incomplete. Modern theories are also incomplete but they’re getting better and better with every research study. So much so that although some of the fine details are still being refined we now have more than enough evidence to talk about the ‘fact’ of evolution in all but the very strictest, scientific terms where ‘theory’ is as certain as one can ever be.
That’s because, if it wasn’t true, evolution would be easy to falsify. The esteemed English biologist JBS Haldane, when asked what discovery would falsify evolution retorted:
“Fossil rabbits in the Precambrian”
That’s because, according to the theory of evolution (and it is a theory – it’s not just a hypothesis) rabbits didn’t evolve until well after the Precambrian era (around 500 million years ago) so fossil rabbits in those early geological layers would pretty much discredit all (or at least most) of evolutionary theory. In fact, almost any ‘out of time’ fossils would be a major problem for evolution and a number of organisations have dedicated themselves to trying to find such an anomaly – so far without success.
Remember the principle of falsification – the more you try and fail to falsify a concept the more reliable it becomes.
Contrast this with the idea of creation by intelligent design (the latest incarnation of creationism). It’s hard to think of a single piece of evidence that would falsify creationism because whatever evidence we throw at the problem the creationist will simply say that God designed it that way. Creationism is ultimately unfalsifiable (at least by its own standards) and therefore it’s impossible to prove as well. It’s a perfect example of what Karl Popper would describe as ‘nonsense’ or, in its latest form of ‘intelligent design’ (ID for short), ‘psuedoscience’.
You see the evidence is the thing – that and the lack of sought after falsification. That’s how we know what we know and also why we don’t have to base our beliefs on the origin myths of a handful of middle-Eastern desert nomads who lived several thousand years ago and knew nothing more about genuine scientific inquiry than their ancient Egyptian counterparts who worshipped Osiris and Ra.
The image below is a late addition to this blog, having actually been created for a different post in September 2014. However, it fits here very nicely as well.
Filed under: Evolution, Hard wired | Tagged: confirmation bias, Darwin, demarcation problem, evolution, fact, falsification, Haldane, hypothesis, intelligent design. creationism, Karl Popper, rabbits in the precambrian, science, theory | Leave a comment »