A recent Harris poll asked Americans “Do you believe in Darwin’s theory of evolution?” Others more eminent have commented on the answers; I would like to comment on the question.
Darwin, of course, never used the word “evolution,” but let that pass. As for the rest, it would be difficult to cram a larger number of serious errors into so small a space. Errors of presentation, of logic, and of scientific and historical fact, all of which play into the hands of our Creationist opponents.
Start with the obvious, the word “theory.” In common language a theory always involves speculation. In academic discourse, it means a coherent set of ideas that explain the facts. Calling something a theory in this sense tells you nothing at all about how certain it is. A theory can be wrong (phlogiston theory), known to be approximate from the outset (ideal gas theory), very close to the truth but since improved on (Newton’s theory of planetary motions), or as certain as human knowledge ever can be (number theory in mathematics). Of course you can explain all this, but you should not put yourself in such a vulnerable position in the first place. It wastes time in debate, or in the classroom. It puts you on the defensive, and thus, paradoxically, confers legitimacy on the attack. It allows the focus to shift from what we know about the world to the words we use to talk about it. This takes us away from science to the domain of the philosophers, lawyers, and expositors of Scripture who are fighting on behalf of Creationism.
And so it distracts from what you should be talking about, namely the facts. Evolution, whether we mean changes in the genetic make-up of populations over time, or the common descent of living things on earth, is a fact. It is supported by, and explains, innumerable more specific facts concerning the fossil record, molecular phylogeny (the same kind of evidence that is used every day in DNA paternity tests), the frozen-in historical accidents of organs that have lost or changed their function, the distribution of species throughout space and time, and much more besides. Creationism cannot explain these facts, except by appeal to the whims of the Creator.
Next “Darwin’s.” Darwin did indeed have a theory, as independently had Wallace, which was that different species had arisen gradually by natural selection operating on variation. This he supported by meticulous observation, but the range of evidence available to him was far more limited than what we have today. He lamented the poverty of the then known fossil record, laments that Creationists echo to this day as if nothing had changed. He knew nothing about mutations or even about the existence of specific genes, and so he had no idea how new variants could arise and spread. His assumption of gradualism is in contrast to later ideas such as punctuated equilibrium, and we now know that much if not indeed most variation arises through neutral drift. Thus not only do we know far more facts about evolution than Darwin could have dreamt of, but our theories, too, incorporate numerous additional concepts.
Finally, worst of all, “believe in.” Believing always carries with it the feeling that disbelief is an option. Some members of the jury believe the witness, others don’t. Some people believe that Hillary Clinton will be the next President of the United States, but no one would say they “believe” that Barak Obama is the current incumbent, because no sane person doubts it. I don’t “believe in” atoms, or gravity, or quantum mechanics, because I regard them as established beyond dispute, although our notions about them will no doubt continue to change as we learn more. And exactly the same is true of evolution.
Does it matter? Yes, it matters enormously. Creationists often maintain that evolution and Creation are both beliefs, whose respective advocates differ, not about observable facts, but about how those facts are to be interpreted. They obsess about Darwin, referring to evolution as “Darwinism,” and to those who accept this reality as “Darwinists.” The aim here is to bypass 150 years of experimental and intellectual discoveries, to bog us down in the day disputes of the late 19th century, or even (“Darwin’s doubt,” see here and here) to enlist Darwin himself as an unwitting ally. And they contrast evolution, as “only” a theory, with facts or even with scientific laws, in order to claim that it is far from certain and that different views deserve a hearing.
Most people have not thought long and hard about evolution. And in the US at least, much of what they have heard about it will have come from its theologically motivated opponents. These opponents, whether through “statements of faith” that make obscurantism a virtue, or through “academic freedom bills” that disguise telling lies to children as open intellectual debate, use carefully crafted words to stake spurious claims to the moral high ground.
We should not, ourselves, be using words that help them do this.
Don’t say “Darwin” when you mean “evolution”. It’s about as useful as saying “Dalton” when you mean atoms. Our understanding of atoms has moved on enormously since Dalton’s time, and our understanding of evolution has moved on similarly since Darwin’s. Neither of them knew, or could have known, the first thing regarding what they were talking about, and both would be delighted at how thoroughly their own work has been superseded.
Dalton didn’t know anything about the forces that hold atoms together, which depend on electrons and quantum mechanics. In fact, he didn’t even know about electrons. Darwin was equally ignorant about the nature of biological novelty, which comes from mutating genes. In fact, he didn’t even know about genes. Chemistry has advanced enormously since Dalton, just as biology has advanced enormously since Darwin, although atoms remain central to chemistry in much the same way that evolution remains central to biology.
So why is discussion of evolution still saturated with Darwin’s name? In part, I think, because that’s the way the opponents of evolution want it. By identifying evolution with Darwin, they continue to breathe life into the controversies of the mid-19th century. At the same time, it helps them pretend that modern biology is just one individual’s point of view, rather than a mature science based on the work of thousands of investigators. Very recently, creationists have taken to invoking Darwin himself for their cause, in such titles as Darwin’s Doubt and Darwin Strikes Back. This is an extremely powerful rhetorical tool; if even Darwin was puzzled by [whatever], surely we “Darwinians” should be too. Closely related is the device of presenting creationism under the guise of even-handed debate, as when a creationist pseudo-textbook (which mentions Darwin on almost every page, but not in the index) calls itself Explore Evolution; the arguments for and against neo-Darwinism, or in the list below, where a creationist comic goes by the name, What’s Darwin got to do with it? A friendly discussion …
And while we’re on the subject of unhelpful language, don’t say “theory of evolution” when you mean the well-established facts of historical and continuing change over time, and of common ancestry. And if you find yourself in the position of explain the difference between a scientific theory (coherent intellectual structure developed to explain a range of observations), and the use of the word “theory” in everyday use (provisional hypothesis), you have blundered into a morass. Back out again.
But back to Darwin. You can see what I mean if you just look at the names of the books written by the new enemies of scientific biology, from Darwin’s Doubt (Meyer, 2013) all the way back to Darwin’s Black Box (Behe, 1996) and beyond. This week I came across further examples, The Darwin Conspiracy (Roy Davies, 2006), which portrays Darwin as a plagiarist, and, while checking its details, an even more lurid book of the same name by John Darnton, which portrays him as a murderer. To be fair, Darnton does not pretend that he is writing anything other than fiction, although surely he was writing with half an eye on the creationist market.
To test my idea, I went online to Amazon.com, and typed “Darwin” and “Darwinism” in the search window. Here are some of the books by creationists that I came up with; a lot of the names were all too familiar, but I never realized that Rick Santorum had actually got his name on a book:
Darwin’s Doubt (Meyer, 2013)
Dehumanization: A Product of Darwinism (David Campbell, 2012)
How We Got Swindled By Wall Street Godfathers, Greed & Financial Darwinism (E. Henry Schoenberger and David Satterfield, 2011)
Evolution by Intelligent Design: Debate is Over – Darwinism is Extinct (Gabor Lingauer, 2011)
Exposing Darwinism’s Weakest Link: Why Evolution Can’t Explain Human Existence (Kenneth Poppe, 2008)
Explore Evolution: The Arguments For and Against Neo-Darwinism, (Stephen C. Meyer, Scott Minnich, Jonathan Moneymaker and Paul A. Nelson, 2007)
The Edge of Evolution: The Search for the Limits of Darwinism (Michael Behe, 2007); Since Behe clearly believes that biological complexity is the work of a designer who operates independently of natural laws, I include Behe as a creationist, although he would deny this)
Doubts About Darwin: A History of Intelligent Design (Thomas Woodward, 2007)
Darwin’s Nemesis: Phillip Johnson and the Intelligent Design Movement (William A. Dembski and Rick Santorum, 2006)
Darwin Strikes Back: Defending the Science of Intelligent Design (Thomas Woodward and William Dembski , 2006)
The Politically Incorrect Guide to Darwinism and Intelligent Design (Jonathan Wells, 2006)
Reclaiming Science from Darwinism: A Clear Understanding of Creation, Evolution, and Intelligent Design, (Kenneth Poppe, 2006)
The Naked Emperor: Darwinism Exposed (Antony Latham, 2005)
Uncommon Dissent: Intellectuals Who Find Darwinism Unconvincing (William A. Dembski, 2004)
Darwinism, Design and Public Education (John Angus Campbell and Stephen C. Meyer, 2003)
Darwinism and the Rise of Degenerate Science (Paul Back, 2003)
The Collapse of Darwinism: Or The Rise of a Realist Theory of Life (Graeme D. Snooks, 2003)
Human Devolution: A Vedic Alternative to Darwin’s Theory (Michael A. Cremo, 2003)
The Case Against Darwin: Why the Evidence Should Be Examined (James Perloff, 2002)
Moral Darwinism: How We Became Hedonists (Benjamin Wiker and William Dembski (Jul 12, 2002)
Darwinism Under The Microscope: How recent scientific evidence points to divine design (James P. Gills, 2002)
Shattering the Myths of Darwinism (Richard Milton, 2000)
What’s Darwin Got to Do with It?: A Friendly Discussion About Evolution (Robert C. Newman, John L. Wiester and Janet Moneymaker, 2000)
Evolution Deceit: The Scientific Collapse of Darwinism (Harun Yahya and Mustapha Ahmad, 1999)
Tornado in a Junkyard: The Relentless Myth of Darwinism (James Perloff, 1999)
Defeating Darwinism by Opening Minds (Phillip E. Johnson, 1997)
Darwin’s Black Box (Michael Behe, 1996)
Darwinism, Science or Philosophy? (Phillip E. Johnson et al., 1994)
Darwin on Trial (Phillip E. Johnson, 1991)
Darwinism : The Refutation of a Myth (Soren Lovtrup, 1987)
There are also references to “materialist neo-Darwinism”, but since I don’t pretend to know what a “materialist” is, and whether I or for that matter Darwin would qualify, I decided to let that go.
And so on, all the way back to The Refutation of Darwinism: And the Converse Theory of Development; Based … Upon Darwin’s Facts, (T Warren O’Neill, pre-1923)
This is my unauthorised summary of the talk that Jerry Coyne gave to the Glasgow Skeptics on Monday, November 26. It is no substitute for reading his outstanding book, Why Evolution is True, but I for one found it useful to see the arguments collated so succinctly.
Jerry discussed the distinction between the common and the scientific use of the terms “true” and “theory”. True, he suggested, means so well supported by evidence that it would be perverse to deny it. In principle all scientific truths are provisional because revisable, but IMO that is no reason for scientists to sound tentative all the time, since the same can be said of all our claims to knowledge about the world. Theories in science, as he very clearly explained, are the conceptual frameworks that we set up to make sense of facts, but in contrast to the common use of the word carry no suggestion of uncertainty. Examples are atomic theory, and the germ theory of disease, as well as the theory of evolution. He then went on to say that evolution had moved from theory to fact. This I think is a philosophical category mistake, though I am not sure that this matters to anyone except philosophers. I prefer to distinguish between the facts of evolution (e.g. the historical facts of shared ancestry) and the theory (referring to a historical context, or else meaning specifically the overarching conceptual framework).
The theory of evolution has five components:
- Evolution, i.e. change in populations, happens.
- The process is gradual, taking hundreds or thousands of years, or longer.
- Evolution leads to speciation, i.e. to the separation of an ancestral species into two descendants.
- As a corollary, distinct species share common ancestors, and indeed all life on Earth shares a common ancestry.
- Natural selection is a major driver of evolution, and is the sole process that causes adaptation and the appearance of design.
(I would note here that there is room for fruitful disagreement, since other reputable biologists come up with different definitions. I also wonder whether adaptation, like speciation, is much more easily recognised after the fact, and whether, given the existence of non-adaptive drift, the linking of adaptation to selection is tautologous.)
This theory makes a number of predictions:
- The first life forms should be simple, with complexity increasing with time in the fossil record.
- Lineages should change and split. Example, split in Rhizosolenia, an indicator species diatom whose changes can be followed in ocean core samples
- Common ancestry implies the existence of transitional forms, such as feathered dinosaurs. These need not necessarily be at the actual point of speciation, but can be identified by their possession of some of the traits that became specific to their descendants. Example, Sinornithosaurus, a flightless feathered dinosaur, intermediate between theropods and birds.
- These transitional forms should appear at the right time in the fossil record. Example, 10 major intermediate forms in the correct order over a 48 million year window between a terrestrial ancestor, identified by details of ear structure, and present-day whales. Another example; the discovery exactly where predicted, in Devonian strata, of lobefish-tetrapod intermediates [see Your Inner Fish, by Jerry’s colleague Neil Shubin]
- The course of evolution should leave bad designs in place. Examples, the male human prostate which unnecessarily surrounds the urethra and presses up against the bladder; ear wiggling muscles which only some of us can operate
- We should be able to see evolution occurring, as in Lenski’s work. We have even observed 300 cases, in a relatively short time that we have been carrying out observations. Under strong selection pressure, we can see changes within a single generation, as with the Galapagos finches faced with changes in the kinds of food available.
There are also examples of retrodictions, things that are not strictly predictions, but make sense only in the light of evolution. These include:
- The appearance in embryos of ancestral features not present in the organism itself. Examples include hindlimb buds on embryo dolphins, and body hair and tail on human embryos.
- The presence of vestigial organs, such as hindlimb and pelvis bones in the grey whale, unconnected to the rest of the skeleton.
- The presence of “dead” (identifiable but non-functioning) genes corresponding to capacities present in ancestors but now lost, including, in humans, genes involved in vitamin C synthesis and some of those involved in the development of olfactory receptors. Human embryos at four weeks include a yolk sac, and humans have dead genes for yolk production.
- Biogeography, including in particular the difference between continental islands, whose fauna relate to that of the landmass to which they were once joined, and oceanic islands, whose endemic fauna are restricted to species such as birds and insects capable of migrating across the open ocean, although other species can flourish and even become plague species when introduced by humans. This is an argument that the creationists have not even attempted to answer.
- Bad design, as evolution is constrained by its past.
One significant prediction is that we should be able, to the extent that our short observation time permits, to see evolution in action, and this is what happens.
The question of the origin of new information came up in questioning. Jerry gave as an example what happens after gene duplication; the two copies can become selected for different functions, as in the variations of haem proteins. (My own favourite example is the duplication and reduplication giving rise to Photosystems I and II, each of which contain two distinct but related subsystems.)
If evolution is a scientific theory, it must be open to falsification. (Here Jerry follows Popper, whose views I think are now regarded as too simple. Theories of merit are generally modified, or subsumed within larger theories, rather than being simply rejected in the face of counterexamples. I would argue that the theory of evolution has been modified, to include such factors as neutral drift, much as atomic theory has been modified to take account of transmutation, but that such modifications are in no way a sign of weakness.) Possible falsifiers include:
- Fossils in the wrong place.
- Adaptations within a species that benefited only some other species, or, more generally, that conveyed no advantage to their possessors or their relatives, or that could not be achieved step-by-step.
- Absence of genetic variation.
Again, I see room for fruitful disagreement, in particular about what would falsify, and what would merely require minor tinkering. A number of questions come to mind. Would group selection require rejection of the theory, as I think Jerry was close to suggesting?