How Do We Know Something Really Happened If We Weren't There to See It?
March 10, 2014 | Revolution Newspaper | revcom.us
Following is an excerpt from The Science of Evolution and the Myth of Creationism: Knowing What’s Real and Why It Matters by Ardea Skybreak, published in 2006.
There are actually many different "categories of evidence" which combine to confirm the basic picture of how life has evolved on this planet. This includes evidence from the fossil record (which shows a series of successive changes in plant or animal lines spread out over millions of years) and evidence from molecular biology (which backs up the fossil record and which reveals the degree to which different evolutionary lines are more closely or distantly related according to the degrees of similarity or difference of their DNA). Such mutually reinforcing categories of evidence are reinforced further still by evidence stemming from developmental biology and embryology, and even from the patterns of distribution of species around the globe. All these different kinds of evidence, taken together, leave absolutely zero doubt that all living species on this planet are related to each other and are the products of descent with modification from a series of common ancestors.
The Science of Evolution and the Myth of Creationism
Knowing What's Real and Why It Matters
by Ardea Skybreak
"This book will be of tremendous benefit to many..."
— Richard Leakey
The Creationists often like to complain that "nobody was around" to "see" evolution taking place over hundreds of millions of years, so it's just an unproven story. But the fact that we weren't around to witness past events doesn't mean they didn't take place, and it doesn't mean we don't have ways of figuring out what happened. Think about it: evolutionists figure out how life-forms repeatedly changed and diversified over time; astronomers and cosmologists figure out how galaxies and solar systems came into being billions of years ago and how they too change over time; historians and anthropologists figure out how humans organized their societies thousands or tens of thousands of years ago; molecular scientists and particle physicists figure out the characteristics of chemical bonds and the interactions of sub-atomic particles they cannot directly "see"; linguists figure out how current human languages evolved through a series of step-wise cultural modifications of much older languages which were spoken by people who have long ceased to exist. We weren't there to directly "see" any of these changes happening, but we do have techniques which we can use to figure out a lot of what happened in the past.
In all these so-called "historical sciences," there are scientific methods which make it possible for us to uncover the left-over marks of the past— those things which "carry over" through time and which are still present in modern-day systems and entities. Things such as the anatomical similarities of body structures which link a modern species to an ancient fossil ancestor, or things such as the similarities in grammar and vocabulary of the French, Spanish and Italian languages which mark them as closely related to each other and all derived from their ancient Latin ancestor language. All the historical sciences contribute to building up human knowledge through investigations of such historical ties and through the process of historical inference, deducing from the actual concrete evidence comprehensive theories which have the power to consistently explain a number of different related processes and phenomena. Historical scientists come to achieve great confidence in their theories (and widespread consensus, as is the case with the theory of evolution) whenever they detect clear patterns of consilience of evidence (which simply means that lots of different streams of evidence, coming from many different directions, all point to the same conclusions and reinforce our understanding of something, such as when the molecular evidence and the evidence from the fossil record both agree on when two evolutionary lines diverged in the past).
Furthermore, in the historical sciences (including the science of evolution) scientific methods are used to make predictions which can then be tested: predictions both about what we should be able to find, and also predictions about what we should not be able to find, if a particular theory about the past is true. And scientists do actually go out and test these predictions in the real world. As just one example, we can predict that if the theory of evolution is true, we should be able to find step-wise progressions of certain anatomical modifications in series of fossils arranged by age (and we do find this); and we can also predict that if the theory of evolution is true we should not be able to find something like a human fossil embedded in a rock layer containing dinosaurs, since everything we understand about how evolution works tells us that humans evolved long after the dinosaurs had become extinct (and in fact fossils of dinosaurs and of human ancestors are never found in the same rock layers). So, unlike "religious beliefs," scientific predictions (including predictions made about the processes involved in evolution) are actually testable and verifiable. This, probably more than anything else, is why there is such a strong consensus among scientists the world over concerning the basic facts and principles of evolution.
Like any good scientific theory, the theory of evolution is "falsifiable"—which simply means that it is possible to conceive of any number of different ways it could be proven to be false (and therefore rejected and discarded) if certain kinds of evidence (evidence fundamentally incompatible with the theory) were ever found. Any scientist will tell you that it is easy to make a list of things which, if they were ever found—whether in the fossil record, in the DNA of organisms, in the anatomy and patterns of development of living plants and animals, or even in the patterns of distribution of species on earth—would leave scientists no choice but to reject the theory of evolution as false. But in the more than 140 years since Darwin first proposed the basic theory of evolution, there have been innumerable scientific studies and experiments which have supported the theory of evolution, but there has never been a single shred of concrete evidence, in any field, which, from a scientific standpoint, raises any doubts about or calls into question the basic facts and fundamental principles of evolution. Not one. No wonder so many scientists consider that evolution is one of the "very best supported theories in all of science"!
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