Posted: Dec 09, 2010 4:04 am
by Durro
Well, one of my pet peeves when it comes to popular misconceptions is the statement that "The Theory of Evolution is only a theory". With that in mind, here's my submission.



Evolution : Is it “Only a Theory” ?

For those of you who are contemplating taking a plane flight in the near future, I'd like you to please keep one important and quite sobering fact in mind - the highly combustible, fuel laden, thin aluminium winged tube you’re thinking about boarding and streaking across the sky at speeds comparable to those of bullets, only works by using a Theory of Aerodynamics. That’s right, aerodynamics is only a theory. It’s never actually been scientifically proven that planes can fly and from the sheer number of them that crash each year - to the startled surprise of everyone concerned - it would be fair to say that clearly this theory has some serious issues.

Now if you read the above paragraph and sat there nodding sagely in agreement, then this article is for you. This short essay will endeavour to explain in fairly simple language why Evolution is best explained by a scientific Theory and why that also means in scientific terms that the Theory of Evolution is as truthful and as solid as anything you’re likely to find in the realm of science. Evolution is as real as Gravity and in many ways, is understood far better and has more evidence for it than Gravity. It's true that scientists can observe and measure many effects of gravity and make many predictions about gravitational forces but, in what may come as a surprise to you, they're not actually 100% sure what causes gravity. Even more galling, conventional concepts of gravity simply break down and don't apply at the subatomic level - apparently quarks, gluons and leptons never got the memo and go about their lives largely unaffected by gravity. However, scientists are very confident about the cause and effects of Evolution and the resultant scientific description is called "The Theory of Evolution".

The term “theory” is tossed around quite liberally these days and consequently, the strict scientific use of the word is chronically misunderstood. Intriguing characters expound colourful “theories” about who really built the pyramids or explain their pet "theory" about how Elvis faked his death and is leading a low profile life working in a 7-Eleven store in Buttplug, Tennessee. There’s even a “theory” about how shape-shifting alien lizards have secretly infiltrated governments and royal families around the globe to create a New World Order and I for one welcome our new reptilian overlords :bowdown: [/hedge betting]. However, as is the case with lawyers, 90% of all “theories” give the rest a bad name. The popular use of the word “theory” has become synonymous with “hunch”, “guess” or “idea” within the general community or worse, associated with the much derided term, “conspiracy theory”. Now while this may be fine for colloquial use or for creative flights of fantasy told by wide-eyed, dishevelled looking men with aluminium foil on top of their heads, in scientific circles the term “Theory” has an altogether different and far more substantial meaning.

In science, a Scientific Theory is not a mere guess or speculation. A Theory is a comprehensive and accurate description of natural phenomena. A Scientific Theory is supported by the best evidence available to hand and it can be used to accurately predict the outcomes of experiments and/or naturally observable events. A Scientific Theory can be verified independently by others and stands up against intense efforts to falsify it. Theories may be modified and improved as further evidence becomes available.

Examples of well known Theories include the previously mentioned aerodynamics - by the way, just so there are no misunderstandings, it’s mechanical failure, pilot error, adverse weather or other factors that cause plane crashes and not any failure of the Theory of Aerodynamics which is also a robust, accurate description of a natural phenomenon. Other Theories which are scientifically accurate, factual and evidentially supported include the Theories of Relativity, Gravity, Electromagnetism, Plate Tectonics, Nuclear Theory, Cell Theory, Germ Theory and so on. The workings of the computer monitor you’re reading this article on can be explained by Electromagnetic Theory, Germ Theory explains why you last caught a head cold, Nuclear Theory explains how atomic bombs cause so much devastation and the Theory of Evolution explains why you are how you are as a living organism.

Some people mistakenly believe that a scientific Theory goes on to become a “Law” once it’s been proven. This is fallacious, for Theories and Laws are actually different but equally accurate concepts in science. In essence, a Law describes the strict relationship between two or more variables or, to put it more simply, how something works, often with mathematical formulae involved. A Scientific Theory describes why things work and provides a comprehensive description and explanation of the mechanisms of various natural phenomena. In fact, there are sometimes both Laws and Theories which govern the same phenomenon in a complimentary manner. The Theory of Gravity explains why gravity acts the way it does while the various Laws of Gravity describe the relationships between force, mass and velocity of gravity is put into effect.

In science, a "fact" is essentially an observation or a data point. The evidenced, undeniable observation that species change over time (Evolution) is a fact. We have the fossils, we have the genetic interrelationships, we've even witnessed it happen within our own lifetime in both nature and the laboratory setting. This fact needs to be explained with references to various laws, hypotheses and other observations - and this is the Theory of Evolution. Like any other scientific Theory, it is open to scrutiny, objective assessment and experimentation. To date, nobody has been able to falsify the Theory of Evolution and in legitimate scientific circles, the Theory is uniformly accepted as the truth. It is the most accurate, most comprehensive, most evidentially supported explanation for the phenomenon of Evolution. If anyone claims that they can falsify the Theory of Evolution, there’s undoubtedly a Nobel Prize with their name on it waiting for them...but only if they can substantially back up their claims with a comprehensive alternative hypothesis, sound evidence and accurate predictions that is ! The claim that "My magic man did it !!!" does not constitute evidence, unfortunately for those who wish-think otherwise.

Scientific Theories do not get proven. "Proof" in science is the realm of mathematics and logic, where strict inviolable relationships exist and can be shown to exist without deviation, exception or variance. That the circumference of a circle equals 2 x pi x the radius of the circle can be proven. However, other areas of science are always open to new evidence to support, refine or even falsify a scientific theory. In fact, some scientists spend a great deal of time not so much trying to prove scientific theories as vigorously testing them to try and find chinks in the armour. The Theory of Gravity explains why you're not likely to spontaneously float out of your chair and hit your head on the ceiling while you are reading this, but there's always the incredibly small chance that this could be shown to be wrong (I hope you don't bump your head too hard if it does happen). And so in science, we leave open the remote possibility that even a robust Theory could be falsified whilst at the same time, acknowledging that some Theories are so strong and so unlikely to be falsified that they are simply accepted as fact. The Theory of Evolution is one of these. The jury is still out on Gravity though, so perhaps hold on to your chair just in case.

Falsification is the process which can destroy a Theory. "Falsifiable" does not mean that a Theory is incorrect or weak in any way, but rather that if it is possible that the Theory is incorrect or inaccurate in any way, there actually exists a tangible means for testing and showing this is so by observation and/or experiment. "Falsifiable" equates to "testable". If an accurate experiment or observation does not fit in with a Theory’s predicted outcome, then the Theory may be adjusted to account for the discrepancy where possible - making the Theory more accurate in the process - or, if the discrepancy is significant, the Theory may be regarded as inaccurate. Newton's Theory of Gravity have been superceded by Einstein's improved work on gravity and relativity, but although Newton wasn't entirely accurate, this work was close enough and useful enough to send manned space rockets to the moon. A previously held Theory that is shown to be slightly inaccurate may retain some measure of usefulness in the real world, as Neil Armstrong could testify to.

Evolution is both theoretically and practically able to be falsified by a number of other non-biological scientific fields. When the Theory of Evolution was proposed by Charles Darwin, DNA was completely unknown, electron microscopes were non-existent and many of the transitional fossils we are now aware of were yet to be discovered. The age of the universe and our planet were not known, radiometric dating wasn’t yet invented and the field of plate tectonics wasn't even a twinkle in it's father's eye. Any of these later scientific discoveries and data from many other co-existing fields of science could have been applied to and subsequently used to falsify various aspects of Evolution but, quite simply, none have been able to achieve this. In fact, these disparate discoveries have actually served to strengthen the evidence for the Theory of Evolution and increase our understanding of the Theory, which has been refined and improved over the last 150 years.

For example, falsification could have been and still may be achieved by finding a single fossil in the wrong geologic strata; the layer of sediments and rocks laid down over millions of years which can now be dated accurately. JS Haldane famously quipped that the Theory of Evolution could be overturned by finding a fossilized rabbit in the Pre-Cambrian. But out of the millions of fossils unearthed around the world, not a single one (deliberate hoaxes aside) has been found in a chronologically discordant rock stratum or sediment layer. Not one. In fact, the fields of physics, chemistry, anatomy, cellular biology, molecular biology, astrophysics, geology, palaeontology, palaeobotany, plate techtonics, seismology and so on could each conceivably produce contradictory evidence that falsifies the Theory of Evolution, but the exact opposite is actually the case. All of these fields provide data, observations and scientific principles which strongly support the reality of Evolution and the accuracy of its scientific explanation, The Theory of Evolution.

There are no alternative explanations that explain biological phenomena better than Evolution. Suggestions such as the ideologically driven “intelligent design” are not falsifiable. Unfalsifiable hypotheses have no practical use as there are no physical mechanisms to test them and they have no interaction with real life. They are simply irrelevant to science and, truth be told, to reality itself. We cannot disprove that the famous Russell's Teapot is orbiting the sun between the Earth and Mars. However, that proposition is not only unfalsifiable, but so absurd that it is not worthy of consideration for anything other than an intellectual exercise on what unfalsibility is. ID relies on an unknowable, undetectable, alleged supernatural agent that does not interact in the material universe (if it did, its actions could be detected and supported/falsified) and so ID is an irrelevant and vacuous argument to put forward in opposition to an accurate, evidenced, well understood physical process. ID has a distinct absence of supporting evidence and quite conversely, has been contradicted by enormous amounts of genuine evidence in favour of the Theory of Evolution. "Intelligent Design" is not a Scientific Theory - it is merely a speculative idea and truth be told, a very poor one at that.

Without wishing to write a Biology text, just some of the evidence for The Theory of Evolution worth mentioning includes :-

• The anatomical and genetic relationships between organisms
• Transitional forms between species
• Observed Evolution in nature and in laboratory settings
• Vestigial anatomical structures
• The bio-geographical spread of living creatures
• DNA similarities and functional redundancies
• Endogenous retroviral damage to DNA that can be tracked between related species with common ancestory
• Fossil records
• Observation of mutations.
• Artificial selection’s similarities to natural selection.

And so on. A more comprehensive list of evidences for Evolution can be found in the Talk Origins Archive at

The evidence against Evolution is…well, nonexistent. The Theory of Evolution IS falsifiable, in that it is quite possible to find evidence to falsify it should that evidence exist. We know what to look for...but it's simply not there. No ideological opponents have been able to find any evidence or make any predictions that have falsified the Theory. When ID proponents or religious figures attack Evolution, it is with either a near complete ignorance of real science, a gross misunderstanding of real science, or by employing sheer wilful duplicity and deceit to fool the ignorant and/or the gullible. The ill-named Discovery Institute is but one religious organization deliberately engaged in a campaign of deceit and lies against The Theory of Evolution and their attempts to defend their ancient mythology in the face of modern scientific knowledge range from the bizarre to the (probably inadvertent) comedic genius.

So, the next time you hear someone state that Evolution is “only a theory”, you might ask them if they are prepared to jump off a tall building to test if Gravity is also “only a theory”. I would suggest that the answer would be no, and for good reason. Both Gravity and Evolution are self apparent and supported by voluminous evidence. They are both able to make predictions and others can test their principles via experimentation and/or observation. But of the two, Gravity is more likely to be amended once the workings of the universe are better known and the existence of gravitons and the Higgs Boson is confirmed or excluded. Evolution is a fact. The Theory of Evolution is the truth of the matter and is here to stay. And no amount of lies, obfuscation or deception from anti-Evolution advocates will change the truth.

So, in summary, is Evolution "only a theory" ? The simple answer is no. With regards to describing the mechanisms for Evolution and explaining the diversity of life on Earth, The Theory of Evolution is not "only a theory", it's the only Theory.


I would like to thank Mr.Samsa, who kindly proof-read an earlier draft of my essay and set me straight on a couple of critical points - particularly on the issues of facts, proof & evidence. He also helped me spell some of the big words. :dopey:

Thank you my wise friend. :cheers:

Sources & further reading :

4. ... -t402.html

Edited : 10/12/2010 for a few typos and grammatical snafu's, plus a few extra comments thrown in.