Responses to Some Common Objections to "The Short Proof of Evolution"
[This text, which has been created by Ian Johnston of Malaspina University-College, Nanaimo, BC, in in the public domain and may be used by anyone, in whole or in part, without permission and without charge, provided the source is acknowledged--released January 2005]
The following remarks have been prompted by e-mail objections over the past two years to the article "The Short Proof of Evolution.". They are intended to serve as a response to those who wish to challenge the validity of the case made there for evolution as a general concept explaining the development of animal and plant species, without reference to how that process might actually work. I will not repeat here the case made in that earlier essay. Those who wish to review it can consult the following link: Evolution). The paragraphs below list most of the common objections I have received, together with a brief response to each one.
My most general response to all objections is the following: Would the person making the objection please indicate where precisely the argument laid out in the essay is fallacious? Is there a particular factual claim which is not warranted? Or are the facts correct but the reasoning erroneous? If the response does not directly answer one of those questions but instead raises extraneous issues, then it is not much use as a challenge to the case made in the essay.
Empty Objections
This rubric includes all complaints which have no content. For example, "What you have said proves nothing" or more succinct pejorative comments (often about the personality of the author) or direct appeals to scripture or some unnamed authority. Such objections are, of course, empty, because they offer no reasonable ground for disagreement and merely indicate the writer's displeasure with the conclusions.
Origin of Life Objections
The most common objections to the case made for evolution is the question, "But what about the origin of life?" What about it, indeed? As the article itself makes clear, questions about the origin of life, though addressing a related issue, are red herrings, since evolution concerns itself with the diversity of species once life is established on earth, not with how life first began. So such a question is rather like raising doubts about how steel is made in any argument about how a car engine works. Naturally, the origin of life on earth is a fascinating issue, one which scientists continue to explore. They have come up with a number of hypothetical possibilities, but as yet there is no favourite theory, nothing which has yielded a wealth of predictions which one can easily test to confirm or reject the hypothesis.
Those who argue that because there is no satisfactory scientific explanation at the moment, therefore there cannot be one and that thus some non-scientific (i.e., religious) account is necessary may well be, as so often in the history of science, jumping the gun. Those who wish to focus on this point might like to consider the following questions: Why does life have to have an origin? Could it not have always existed somewhere in this universe or a parallel one?
Objections to Darwin
A number of those taking issue with the case made for evolution point to some real or apparent difficulties with Darwin's account of how evolution proceeds (that is, through natural selection). Again, as the original article points out, such objections are irrelevant. The general case in support of evolution derives none of its strength from Darwin's work and would remain exactly as it is if we had never heard of Darwin or if we decisively refuted his theories. Such objections are easy to make, of course, because scientists themselves are always calling attention to certain problems with parts of Darwin's theory, but they do not affect in the slightest the argument for evolution made in the essay.
The "Fossils are Misleading" Objection
One common objection takes issue with the claim that the rock layers of the earth (and the fossils they contain) indicate a sequence of geological events over a long period of time. Now, this objection has one great merit most of the others lack: it does engage the argument made in the essay by directly challenging one of the three factual claims upon which the argument rests. That, however, is its only merit. For those making this objection are explicitly or implicitly claiming that the geological record was made in a matter of days or weeks by a process as yet unexplained, other than by appeals to miraculous processes. But if we permit imaginatively created miracles designed to answer what we would like to believe to serve as reasonable explanations, then there is an infinite number of possibilities, all equally likely and all equally incapable of verification (for example, the once popular idea that the fossils were planted in the rocks by the devil to mislead human beings). Scientific enquiry achieved its favoured status largely because it delivered us from such irresolvable and sterile disputes.
The fossil record, especially the succession of different fossils in different rock layers, is the most compelling evidence against the view that the earth was created quickly and has always contained the same forms of life and also the reason virtually all serious scientists eventually conceded (often with great reluctance) that the earth has a long history, a narrative that includes the appearance and disappearance of many different species. A particularly compelling point in this narrative is that human remains occur only in the most superficial layers (in graveyards, battlefields, river bottoms, and so on) and are never found in deeper rocks.
The Objection Based on the Absence of Visual Confirmation
Others reject the notion of evolution outright (without reference to the argument) with the simple claim that it cannot be true because no one has ever seen a complete transformation of one distinct species into another (e.g., fish to reptiles). Without such visual experience, so they say, evolution is just a "theory."
Well, of course evolution is a theory, just as gravity, atomic structures, electricity, relativity, DNA, and so on are "just theories." But so what? We do not have direct visual evidence of these things with our own eyes (who has ever seen gravity or an electron or a molecule or a gene with the naked eye?). Most scientific theories involve natural elements that we cannot see. Those who seriously believe that this objection carries any weight need to become more familiar with the nature of scientific enquiry and the meaning of a scientific "proof."
Science does not proceed by demonstrating that certain theories are irrefutably true. It demonstrates by repeated testing that they are not false. The more a theory is confirmed, the stronger the probability that the explanation it offers is correct. And how does such confirmation proceed? There are two main tests. The first is to make a series of predictions based on the theory and then to explore the validity of those predictions. If a prediction holds, the theory has been confirmed; if not, then the theory has been challenged, perhaps even disproved. The second method of confirmation is to see how the theory accounts for new, unexpected discoveries. Can these be explained in terms of the theory? If so, then the theory has been confirmed; if not, then the theory has been challenged or disproved. By these two tests, the theory of evolution is spectacularly successful: it has been confirmed countless times over the past three centuries (at least), and it would take only one discovery to discredit the entire theory (e.g., the existence of a mammal fossil in the lowest rock layers).
This aspect of scientific explanation gives the method its unique power. Unlike some other knowledge claims, discrediting or disproving a scientific theory does no harm to scientific enquiry itself. Quite the contrary. It forces scientists to come up with a more refined or a different theory which can better account for the anomaly, and hence it strengthens the explanatory power of science and of particular scientific theories, like evolution.