Monthly Archives: February 2014

How NOT To Defend Evolution; With Friends Like These Who Needs Enemies?

File:Tree of life SVG.svg Evolution is fact as well as theory. There is no scientific controversy about this. It has advanced way beyond what Darwin could have imagined, and well-meaning commentators who forget this risk doing more harm than good.  (And come to think of it, have I too misframed the problem by using the word “defend”, as if there were something that could sensibly be attacked?)

On Friday, the Forbes Magazine website carried an article entitled Creationism Has No Place In A Science Class. While sincerely intended as a defence of evolution, this article is so laden with rhetorical, logical, historical, and scientific errors that it plays straight into the hands of the creationists. If anyone were to defend atomic theory in the same way that this article defends evolution, the absurdities would be obvious. It is a sad comment on the extent to which we have allowed the enemies of reason to dictate the agenda, that articles like this continue to see the light of day.

To begin at the beginning:

 More than 150 years since Darwin published his Theory of Evolution, it still has the capacity to stir controversy.

 Wrong, wrong, and wrong again. Evolution happened, and continues to happen, and that is fact, not theory. We have theories of how it happens, and all or nearly all of these rely on Darwin’s seminal insights, but we also have direct information that Darwin could not even have dreamed of. It is not evolution itself that stirs controversy, but the nonscientific opposition to it, based entirely on religious obscurantism. And while the article does not define creationism, the only kind of creationism that pretends to a place in the science classroom is the late 20th century absurdity of “creation science,” and its pretentious relative, “Intelligent Design.”

The author goes on to describe a UK academic study of attitudes towards evolution as a “contribution to the debate.” The study’s authors would be horrified, since they themselves take the truth of evolution for granted. The debate to which they are contributing is not about whether we should teach creationism. On the very contrary, it is about how to teach evolution to students who are drawn to creationism for reasons that had nothing to do with science.

The article tells how the Christian Schools Trust claim to teach creationism “in a balanced way.” A little digging would have shown that the Trust has a policy, publicly available through its founder’s Ph.D. dissertation, of teaching evolution in such a way that it will not be believed (I have commented on this dissertation before; see here).

The final paragraph reads:

Critics of evolution claim that it is just a theory for which there is no proof. It is true there is no definitive proof, and nor is there likely to be, but there is a vast amount of evidence in its favour. Whether you choose to believe it is sufficient is up to you, but it is there. By contrast, there is no scientific evidence for creationism. It may be true, but it is a matter of belief and its proper place in schools is in religious studies class. Creationism is not science, and has no place in a science class.

This is even worse than the beginning. Science does not do proof, in the sense of mathematical certainty, but it can and does do proof beyond all reasonable doubt, and that we have for evolution. Consider the fossil record, vestigial organs, frozen in bad design, meticulously detailed anatomical homologies, DNA evolutionary trees that match those based on comparative anatomy, evolution in the laboratory, in nature and under our direction in the farmyard, and the way in which different species are distributed. Any one of these (and there are more) would be enough to convince, were it not for religiously motivated opposition. If this evidence is not sufficiently definitive, I can only wonder what definitive evidence could possibly look like.

And I do not understand the claim that creationism “may be true.” Philosophical creationism, the idea that a god or gods created and guide the universe as a whole, is indeed a belief worth examining in the religious studies class. Creationism as opposed to evolution is something quite different. It is the belief that different kinds of living things owe their existence to separate miraculous acts of creation. Not only is this contrary to the evidence, but it reduces God to the level of an incompetent trickster who needs to keep on cheating. In itself, deserves no more respect than any other intellectual pathology, and the only debate is about how to reach those misled by it.

Image: Phylogenetic tree of life, by Ivica Letunic after iTOL through Wikimedia commons. Vertebrates to left of top centre.

Kelvin, Rutherford, and the Age of the Earth: I, The Myth

File:Lord Kelvin photograph.jpg

Lord Kelvin (Smithsoinian Instituion Libraries collection)

Kelvin calculated that the Earth was probably around 24 million years old, from how fast it is cooling. Rutherford believed that Kelvin’s calculation was wrong because of the heat generated by radioactivity. Kelvin was wrong, but so was Rutherford. The Earth is indeed many times older than Kelvin had calculated, but for completely different reasons, and the heat generated by radioactive decay has nothing to do with it.

Disclosure: in my introduction to the Scientific American Classic, Determining the Age of the Earth, and elsewhere, I have like many other authors repeated Rutherford’s argument with approval, without paying attention to Rutherford’s own warning that qualitative is but poor quantitative, and without bothering to check whether the amount of heat generated by radioactivity is enough to do the job. He thought it was but we now know it isn’t. It was only when chatting online (about one of the few claims in the creationist literature that is even worth discussing) that I discovered the error of my ways.

On the face of it, things could not be plainer. Kelvin had calculated the age of the Earth from how fast heat was flowing through its surface layers. An initially red hot body would have started losing heat very quickly, but over geological time the process would have slowed, as a relatively cool outer crust formed. His latest and most confident answer, reached in 1897 after more than 50 years of study, was in the range of around 24 million years.[1]

Yet on May 20, 1904, there was Rutherford, at the lectern of the Royal institution, talking about a piece of Cambrian rock, and announcing, on the basis of how much of its uranium had decayed to give lead and helium, that its age was some 500 million years. We even have Rutherford’s much quoted account of what happened next:

I came into the room which was half-dark and presently spotted Lord Kelvin in the audience, and realised that I was in for trouble at the last part of my speech dealing with the age of the Earth, where my views conflicted with his. To my relief, Kelvin fell fast asleep, but as I came to the important point, I saw the old bird sit up, open an eye and cock a baleful glance at me.

Then a sudden inspiration came, and I said Lord Kelvin had limited the age of the Earth, provided no new source [of heat] was discovered. That prophetic utterance referred to what we are now considering tonight, radium! Behold! The old boy beamed upon me.

This all seems clear enough. Rutherford is referring to Kelvin’s cooling argument. But this argument is invalid, because it assumes no new source of heat, and such a source exists, namely radioactivity.

The process that was overlooked in Kelvin’s calculations was also, indirectly, responsible for producing these folds.

Or so says the popular myth. The truth is more complex, and more interesting. For a start, Kelvin’s “prophetic utterance” did not refer to the Earth at all, but to a separate calculation of the age of the Sun. We know how brightly the Sun shines, and hence how rapidly it emits energy. If we knew how much energy it had to start with, and assumed that it wasn’t being added to, we could simply divide the initial amount by the rate of depletion, to estimate how long it would be able to shine. Kelvin performed such a calculation many times. As source of energy, he invoked the most intense source known to him, namely the gravitational energy released when the Sun collapsed from a diffuse cloud of gas to its present size. This led him to conclude in 1862 that the age of the Sun was in the range of 10 million to 100 million years (subsequently refined to around 20 million), and that “inhabitants of the earth can not continue to enjoy the light and heat essential to their life for many million years longer unless sources now unknown to us are prepared in the great storehouse of creation [emphasis added].” These are the prophetic words that Rutherford was referring to.

If Rutherford thought that the energy of radioactive decay was fuelling the Sun, he was greatly mistaken. The philosopher Auguste Comte had written in 1835 that we would never know the internal composition of the heavenly bodies.[2] He was wrong. Pass electricity through a gas or vapour, and it will emit light at specific frequencies that depend on the elements present (one familiar example is the sodium yellow of street lights). There are dark lines in the solar spectrum, and by 1860 the German chemist Kirchoff had shown that their frequencies match these characteristic emission lines.[3] So the chemical composition of the Sun’s outer layers was already well-known, and the fractional abundances of the heaviest elements, including almost all those that exhibit radioactivity, are quite negligible. And we now know, as Rutherford could not, that radioactive decay does not generate enough energy. Even if abundant supplies of the radioactive elements were concealed within the Sun’s interior, they would not suffice to fuel the Sun for Rutherford’s 500 million years, let alone the 4,500 million years, with as much still to come, required by current estimates.[4] It was not until 1920 that the source of the Sun’s energy was correctly identified as the fusion of hydrogen to helium, and while this was soon generally accepted, quantitative confirmation by measurements on the neutrinos produced had to wait until 2001. Using Einstein’s famous mass/energy equation and the masses of the isotopes involved, it is easy for us to calculate that the fusion of hydrogen to helium is some thirty times more productive of energy than the decay of the same mass of uranium to helium and lead; but Rutherford in 1904 could not have known of the relationship between mass and energy, or the precise masses of the relevant isotopes, or even that such things as isotopes existed.

But what about the age of the Earth itself, and Kelvin’s cooling calculation? This is what I had for many years assumed that Rutherford was talking about, and it turns out that radioactive decay is no real help here either. Measurements on granite in the early years of the 20th century suggested that radioactivity could fully account for the amount of heat being radiated out to space, and that the Earth might even be heating up. But we now know that granite is not representative of the Earth as a whole. The total rate of heat production by radioactive decay is currently estimated at around half the amount that the Earth emits to space, so simplemindedly we might imagine that this extends Kelvin’s calculation by a factor of two. Maybe a bit more, since by their nature radioactive materials would have been more abundant in the remote past, but this will not make much difference over the few tens or even hundreds of millions of years then under discussion. And even this grossly exaggerates the potential significance of radioactive heating, since all we need to consider is the heat generated in the outermost layers, from which heat has had time to diffuse the surface.

So how could Kelvin’s cooling argument be refuted? The correct argument had been put forward a decade earlier, before radioactivity had even been discovered, by John Perry, one of Kelvin’s own former pupils, and Kelvin had partly accepted the principle of Perry’s reasoning.

To understand what is really happening, we need to consider the different ways in which heat can be transferred. You may remember from school that there are three processes available; radiation, conduction, and convection. Radiation is the process by which the Sun, or the filament of an incandescent light bulb, glows yellow hot; or at lower temperatures the embers of a fire or the coals of a barbecue glow red hot; or, at yet lower temperatures, the Earth loses energy to the coldness of outer space by glowing in the infrared. It is not really relevant to the transmission of energy through opaque material such as rock. Conduction is simply the diffusion of heat through material, as the faster moving atoms of the hotter region jostle against, and share their energy with, their cooler neighbours. The third, and most efficient, heat transfer mechanism is convection. This is the physical movement of hotter material, carrying its heat with it, as in the roiling that takes place in the water when you boil an egg on a stove, or the pattern that forms in the film of oil in the pan if you prefer your eggs fried. Hotter material expands, making it less dense, so it rises to the surface, bringing cold material closer to the heat source.


Convection in a pan over a heat source. Warm (red) material is less dense and rises, allowing cold (blue) material to sink. Image by Eyrian through

Radiation is only relevant when we are talking about the transfer of heat through empty space, or through some transparent medium. Diffusion is simply the statistical spreading out of the extra heat in the hotter material, and is an inefficient process over long distances. By far the most efficient heat transfer mechanism is convection, but this can only take place in a fluid, where hotter and colder material can physically change places.

Back to Kelvin’s cooling rate calculation. This depended, among other things, on assuming heat transfer by conduction, and the rate of conduction was determined by actual measurements on rocks. Now imagine what would happen to Kelvin’s calculation if the actual heat transfer process were more efficient than this. The effect is the opposite of what you would at first imagine. Commonsense suggests that more rapid heat transfer would imply more rapid cooling. Not so. If heat transfer is limited, only a relatively shallow layer near the surface will have had time to contribute. If heat transfer turns out to be more efficient, the cooled layer will be correspondingly thicker, heat will have been conveyed from greater depths, and the total amount of heat conducted through the surface and lost to space will be correspondingly greater. But we know the total rate at which heat is being transferred, from the conductivity experiments and the rate at which temperature increases when we go down a mine, and this acts as a constraint on the calculation. Fixed rate, but a greater total amount because of more efficient heat transfer, implies a longer time. The cooling calculation can therefore be brought into line with Rutherford’s results, and indeed with the even longer times that we now know to be involved, if heat at depth is sufficiently more mobile than Kelvin had imagined.

In 1894, Kelvin’s former pupil and protégé, John Perry, had suggested higher heat transfer as a way of reconciling Kelvin’s age estimates with the hundred million years or so then required by the geologists. Kelvin, rather grudgingly, agreed in principle, and undertook to examine whether the thermal conductivity of rocks did increase as required at high temperature. [5] Within a few months, Kelvin reported a colleague’s response to this question; they did not. Indeed, Kelvin took the opportunity to review the entire question in the most extreme possible light, triumphantly lowering his best estimate of the age of the Earth to around 24 million years, noting that this was in good record with his estimates for the age of the Sun, and claiming that the burden of proof was now back with the geologists. Perry, in reply, drew attention to the fact that Kelvin had totally ignored the possibility that the Earth’s interior was or had been fluid enough to support convection, but Kelvin seems to have passed over this suggestion in silence.

A pity. Convection in the mantle, as we now call the region between the solid crust and Earth’s metallic core, is a cornerstone concept of modern geology. The implications of this, together with an explanation of why Perry waited until 1894 to challenge Kelvin’s calculations (which went back, as we have seen, to 1862 and earlier), and how I belatedly stumbled upon this story as a result of chatting online about the creationist literature, will be the subject of further posts.

An earlier version of this post was published in 3 Quarks Daily

[1] Detailed (and sometimes mildly discordant) scholarly studies hereherehere and here, and references therein.

[2] Comte, Positive Philosophy, Bk II Ch 1

[3] Annalen der Physik 185, 148–150, 275-301 (1860).

[4] Some radioactive elements, such as the newly discovered radium that Rutherford was referring to, do generate heat quickly, but that is because of their rapid decay rate, which implies short half-lives and rules them out as candidates.

[5] Perry, Nature 51, 224-227 (1895); Kelvin’s acknowledgement is at p. 227, his dismissive rebuttal at p. 438, and Perry’s final attempt at persuasion at p. 582.

Darwin, God, Alvin Plantinga, and Evolution II; Plantinga in the Quote Mine and Epistemological Creationism


Professor Plantinga lecturing, 2009

Prof Alvin Plantinga, of Notre Dame University, is perhaps the most distinguished critic of current views on evolution. He claims that if our conceptual apparatus is simply the product of naturalistic Darwinian evolution, it will generally give rise to unreliable results. From this premise he argues that it is unreasonable to accept naturalistic evolution, since[1] if naturalistic evolution were true, our reasons for accepting it would be unreliable. There is nothing wrong with his logic, but his premise rests on a basic misunderstanding of how evolution works.

Disclosure: around the time of the Kitzmiller-Dover trial, Prof Plantinga and I had a long e-mail correspondence, now unfortunately lost during a University mail system upgrade. I remember, however, the final exchange. He said that BeheDembski, and Thaxton, advocates of three different versions of Intelligent Design, had produced arguments that required an answer. In reply, I said that I totally agreed; the answer was, in each case, that they were wrong. Prof Plantinga did not reply.

Disclaimer: I have no credentials when it comes to philosophy. But let me plead in mitigation that Prof Plantinga has no credentials when it comes to evolutionary biology.

According to Plantinga, a belief is warranted when it is produced by cognitive functions working properly, according to a design plan aimed at producing true beliefs. The design plan could be produced by an agent (God, or a super-scientist), or by evolution. This convoluted definition is necessary to bypass cases that puzzle philosophers, such as, is a belief warranted when it happens to be true but we hold it for bad reasons.[2] Plantinga’s position is encapsulated in the title of his 1993 book, Warrant and Proper Function.

I have three problems here. One is the choice of words; design plan and aim have connotations of foresightful agency, and it would be better to use neutral terms such as adaptationand tendency to produce. The second is circularity; how do we define proper function, if not in terms of giving warrant to beliefs when appropriate? The third, which is really a consequence of the second, is that it is useless in real disagreements, because it begs the question. For example, Prof Plantinga tells us that he possesses a sense of the divine, which he regards as a warrant. But how can he know that this is a warrant, unless he already knows that this sense is leading him towards the truth? And what, then, of Darwin’s objection (Part I); how can we have confidence in the beliefs that this sense induces, when those who claim to possess it differ so forcibly among themselves?

Warrant and Proper Function2a

Plantinga is better when dealing with the limitations of our senses. He raises the interesting possibility that while they are not perfect, they are good enough, and that their deficiencies may represent a trade-off between speed and accuracy. This, I suggest, explains some shortcomings but not others. For example, in perspective illusions, such as the parked car illusion, we incorrectly perceive the image of the object further away from us as larger. This is a small price to pay for the ability to judge the real size of distant objects. There are other illusions, such as the disappearing dots, that have no obvious function, but are presumably byproducts of a generally efficient image processing system. There are, however, defects that can only be understood in terms of our evolutionary history. Thus, notoriously, the nerve connections to the mammalian retina run in front of the light-detecting cells, obscuring the view, and there is also a blind spot in each eye, where the optic nerve passes through the retina. If a freshman engineering student came up with such a design, we would gently suggest that he considered changing his major. After all, it doesn’t have to be like that; in the octopus eye, the parts are the right way round.

One of Plantinga’s examples inadvertently illustrates how evolution actually works. He considers[3] the case of an individual with extremely low blood pressure, and a fragile aorta. The low blood pressure restricts his physical activity, but if it rose to what is considered normal, his aorta would burst and kill him. So is the heart acting properly in keeping his blood pressure low? The answer would seem to be, yes, if and only if his design includes a mechanism by which a damaged aorta limits cardiac activity.  (Much as our body temperature control system includes a mechanism that causes fever when we are fighting off disease.) For Plantinga, the heart/aorta example illustrates that we can only define proper function for an organ, including a human organ, in terms of a pre-ordained plan. On the contrary, I would claim, it illustrates the artificiality of imposing, on the complexity of biological forms, the simple criteria more appropriate to artefacts.

Now consider a primitive organism with very little in the way of blood vessels. Such an organism might have a very simple heart, encouraging circulation of fluid. There would be an adaptive advantage in channeling this blood flow, and once that happens, there would be further advantage in improving the performance of the heart. The heart and the circulatory system are under a selection pressure to improve, but only step by step. This is because there would be no advantage, and some cost, if one were to get too far ahead of the other. One can imagine further elaboration, if the creature develops separate organs for exchanging carbon dioxide in the blood for oxygen. Indeed, something like this seems to be what actually happened. A mutation in advance of the proper context would be lethal; a double-circulation heart could not function properly in a codfish. So if we are to apply the concept of proper function to organisms, it needs to be set in its evolutionary context (I do not expect Prof Plantinga to agree).

Throughout, Plantinga makes things far more difficult for himself by his rejection of the natural power of evolution. He makes heavy weather, as philosophers are bound to, of the “problem” of how we know that others have minds. As Plantinga reminds us, this is not a matter of ordinary logic or inference. After all, we are arguing from analogy with our experience of ourselves, i.e. from analogy with a single example. Indeed, unless we suffer from autism, we believe in other minds from the cradle, without arguing about it at all. So when Plantinga discusses how we come to have this belief, or why we should trust it, he can give no explanation other than Providence. However, we are social species, and both survival and mating opportunities depend on social competence. Thus there is strong evolutionary pressure to develop an adequate theory of other minds. There is good evidence that our brains contain “mirror neurons”, which respond to other people’s movements and gestures in the same way as to our own, bringing us as close as separate individuality allows to sharing other people’s sensations. But even without such knowledge of mechanism, we would be well aware, as philosophers have been since Aristotle, of the vital importance to each of us of insight into the minds of others.

The last chapter of the book is what drew it to my attention, with its claim that we cannot have warrant for believing in naturalistic evolution. For the most that naturalistic evolution could guarantee, is behaviour that increases fitness,[4] and Plantinga claims that there is no good reason to suppose that such behaviour requires true belief.

At this point, Plantinga commits a blatant act of distortion by quote mining, of the kind all too familiar to students of the creationist literature, but surprising in a scholar of his stature. He manages to invoke Darwin himself to support his position, with this excerpt from a letter to William Graham:

With me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?

The quotation is genuine, but the meaning is completely distorted, by suppressing its context. Consider the passage in full:

Nevertheless you have expressed my inward conviction, though far more vividly and clearly than I could have done, that the Universe is not the result of chance. But then with me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?

So the question is very narrow and specific; whether we can trust minds evolved from those of animals when they lead us to believe that the Universe had a creator. In Part I, I gave two other examples of Darwin showing similar reticence, because of how our minds evolved. But in both those cases, Darwin is addressing exactly the same question as here, which must have preoccupied him over many years. There is no honest way of recruiting Darwin to support the view that our evolved animal nature makes our minds unreliable on any lesser topic. Yet Plantinga manages to say (p 219[5]), almost immediately after his truncated quotation,

Darwin and Churchland seem to believe that (naturalistic) evolution gives one a reason to doubt that human cognitive faculties produce for the most part true beliefs: call this ‘Darwin’s Doubt’ (emphasis added)

The expression “Darwin’s Doubt” may well be familiar; Stephen Meyer chose those words as the title of his recent book in which he presents a long since deflated[6] perspective (see here and here and here and, if you have access to Sciencehere) on evolutionary change in the Cambrian.

But let that pass.

It is repeatedly clear that Plantinga understands nothing about how evolution works. For example (p 204) he imagines a sadistic dictator “inducing a mutation” into his enemies, which condemns them to a life of pain, and converts their visual fields to a shadowy green screen. He then asks, if possessing this mutation is made a condition for those enemies to breed, whether defective eyesight is now proper function. In reality, it is impossible to induce mutations in individuals who already exist, and the kind of change involved would in any case, even if possible, take many generations. Compare this “mutation” with the distortion actually induced in some pedigree dogs, which have been bred to have faces so flattened that they have difficulty breathing. But this took repeated selection, and close control of bloodlines. (And I would add that the conflict in both these cases between natural and artificial selection once again shows the problems of applying the concept of proper function to organisms.)

In a deservedly much-mocked passage (pp 225 ff), Plantinga tries to describe how a deeply mistaken worldview could still enhance fitness. For example, what if someone thought that it was delightful to be mauled by a tiger, and, at the same time, that the best way to ensure being mauled was to run away from it? Such a combination of beliefs would lead to survival-inducing behaviour, even though each of the beliefs was mistaken. But for this to happen without going through a lethal intermediate stage, each of the mistakes would have to occur in a single step, and both of them would have to happen at once; an unlikely coincidence of events improbable enough in themselves. If Plantinga doesn’t see the problem, I suspect that he has failed to appreciate the step-by-step nature of evolutionary change.

The evolutionary approach, incidentally, defines a role for pain, as Darwin realised (see Part I), and this role is, precisely, to induce correct beliefs about what is harmful. Plantinga’s account of beliefs does not require such preliminaries, and so the problem of suffering is much more acute for him than for a Darwinian.

Back to Darwin’s letter. When it comes to the mundane realities on which survival depends, there are indeed circumstances where we would “trust in the convictions of a monkey’s mind”. We know that monkeys are good at detecting predators, fear them, and signal that fear to each other. If we were in the jungle surrounded by monkeys, and they suddenly show signs of having detected danger, we would be foolish not to pay attention.

I have spoken of monkeys feeling fear. Yet a follower of Descartes would deny that animals have any feelings at all. How could I convince him? Perhaps by such evidence as the monkeys’ facial expressions and vocalisations, how these affect other monkeys, changes in activity in different regions of the brain, adrenaline release, blood flow, and skin temperature, all compared with the effects of fear in humans. Then what about less intelligent animals? Pursuing this route, we will soon find ourselves refining or breaking down the concept of “fear”, and embarking on a research programme, or indeed a family of research programmes, straddling the frontiers between ethology, evolutionary psychology, and philosophy. Such programmes are already well under way.

Our conceptual apparatus is indeed unreliable, but this is just what naturalistic evolution would lead us to expect. For the failings are most evident in areas where our errors would have inflicted the least damage on our fitness, and might indeed have enhanced it.

Such failings are numerous, and here are a few examples. Our common sense (or, as Bertrand Russell called it in Mysticism and Logic [free download here], our intuition) is most reliable on matters of immediate concern. Intuition tells me that I am sitting on a solid chair, in a room that is not moving, and only recently, in evolutionary terms, was it discovered that the chair is mainly empty space, and that the room that is moving eastward at several hundred miles an hour. I see patterns that are not there in reality; but better to see a tiger that isn’t there, hiding in the long grass, than to fail to see a tiger that is. As an infant, I understand physical events in terms of purpose and agency, rather than physical causation, and in some of us this tendency persists into adulthood. No surprise, since as an infant my very survival depends on interacting with other people, and getting them to care for me. I believe in the tribal gods, because this intellectual sacrifice qualifies me for membership of the group, with access to reciprocal altruism and reciprocal trust (see Jared Diamond’s The World Until Yesterday for more on that last theme). And those last few suggestions may or may not be true, but are at least credible, and suggest further research programmes of their own.

Given these failings, how, if at all, can our scientific beliefs be warranted? In 1520, science taught that the Earth was fixed, in 1820 that species were fixed, and in 1920 that the continents were fixed. Few people would now expect to see these views reinstated. So did they have warrant at the time? If they did, how much is a warrant worth? If not, how can we claim that our current beliefs are warranted? These are interesting and important questions, but not, I think, the questions that Prof Plantinga addresses.

Moreover, the problem of warrant is most acute in the very area where Prof Plantinga seems most certain of his own beliefs, namely religion. Here, all believers would claim warrant. But their beliefs are so diverse that, as a matter of arithmetic, most (if not all) of them must be mistaken. Yet here, surely, is the area where an Abrahamic God, desirous of being loved and worshipped, would have been most concerned to design us with access to sound knowledge of His reality.

It is not the naturalistic evolutionist who should be troubled by the problem of reliability, but the Intelligent Design creationist.

Photo by Jonathunder through under the Creative Commons Attribution-Share Alike 3.0 Unported license.  An earlier version of this post appeared here on 3 Quarks Daily

[1] He devotes some 20 closely argued pages to this logical step, but I think I have captured the drift.

[2] If I understand him correctly, Plantinga would say that it is still warranted as long as we are in no position to realise that the reasons are bad.

[3] I have changed the details slightly, in order to make the situation more plausible.

[4] Plantinga generally refers to survival advantage, but fitness, the ability to survive and produce offspring that are themselves fit, is what actually matters.

[5] Page number references are to Warrant and Proper Function, print edition, OUP 1993.

[6] The “Cambrian explosion” isn’t what it used to be.

PhD Thesis of Sylvia Baker, founder of “Christian” (i.e. Creationist) Schools Trust

Events have made it important for this dissertation to be widely known, and its implications discussed. It is freely downloadable at

I am posting a summary of some of the more salient points. This is not so much a normal blogpost, as a simple information resource I had prepared for BCSE, and am now publishing in response to events; editing for tidiness can wait.

Note in particular Tables 7.1, 7.2 (pp 164, 167) regarding the beliefs of students taught by Christian Schools Trust, and the CST 2009 policy on teaching evolution in such a way that it will not be believed, pp 354 ff, attached at the end here. Material from the text is in black or red; insertions and comments in blueEmphasis is added unless stated otherwise.

P31: In one of the very few available studies, Francis and Robbins (2005) have examined the relationship between spiritual health and attending an independent Christian school, particularly in relation to urban living, using the model of spiritual health developed by the Australian researcher John Fisher (Fisher, Francis and Johnson, 2000 ). They consider that there are significant ways in which young people in the new Christian schools enjoy a higher level of spiritual health compared with young people in non-denominational schools and that this will predispose them to become good citizens. Francis and Robbins conclude that:

The positive interpretation of these findings is that Christian schools bring to the urban environment communities committed to shaping purposive young lives capable of contributing to the common good on both local and global levels. Such communities are constructive rather than divisive of urban hope for the future. Urban planners may need to recognise and to value the distinctive contribution made to urban living by the relatively recent movement to develop independent Christian schools (Francis and Robbins, 2005, pp131-132).[No lack of ambition]

P126: 5.5 The target population

The current survey aimed to cover as many as possible of the teenagers to be found in Years 9, 10 and 11 of the new Christian schools, particularly from those schools belonging to the Christian Schools Trust (CST).

Pp126-7: 5.6 The respondents

In the event, 25 schools returned completed questionnaires, of which 22 were schools belonging to the Christian Schools Trust. A total of 695 thoroughly completed questionnaires were returned, of which 673 were from CST schools, leaving just 22 from the three schools unconnected to the Trust. The schools had been asked to indicate how many pupils they currently had registered in Years 9, 10 and 11 at the time that the questionnaire was administered. The Christian Schools Trust schools indicated that they had a total of 782 pupils of this age. The three other schools did not provide this information but given that they only returned 22 questionnaires between them, they were clearly very small schools. The figures indicate that the 673 pupils who completed questionnaires from schools belonging to the Christian Schools Trust amounted to 86% of their total. The responses should therefore provide a reliable picture of the beliefs, views, values and concerns of the young people who are emerging from this sector of the educational scene.

Pp 150 – 151: The schools may well constitute the only setting within the United Kingdom where science education is approached within a creationist framework. For this reason the next chapter will focus exclusively on this issue.

P 152: This survey therefore has the opportunity to make a distinct contribution to the controversial issue of whether or not schools should allow creationism and intelligent design to be taught alongside evolution in science lessons. The importance of the matter was brought into sharp focus by the forced resignation of the Revd Professor Michael Reiss (Baker, 2009b) and it remains a major potential source of criticism for the new Christian schools.

Baker, S. (2009b) Creationism in the Classroom: a controversy with serious consequences, Research in Education, in press. [Actually 83, 2010, 78-88; a mixture of Steve Fuller’s extensively quoted reality-free view of science, what reads as a forceful and justified criticism of hostility towards believers, rather than just towards belief, on the part of some influential members of the Royal Society, and the absurd suggestion that scientific hostility to creationism is enforced by an elite, and may not even represent the views of most scientists.]

P 153: the term …creationism … is often used pejoratively to mean an anti-science position, founded on ignorance and imported in recent years from the United States. However, various forms of creationism have a long history in the UK. The Creation Science Movement (formerly the Evolution Protest Movement) was founded in Britain in 1932 and claims to be the oldest creationist society in the world ( while the Biblical Creation Society, again a British organisation, was founded by academic theologians and scientists in 1976 ( The recent publication The New Creationism (Garner, 2009) provides an overview of the current position taken by British creationism.

Ch 7, at amazing length: extreme criticism of the Theos/Comres survey

158, note how she describes this creationist pseudo-textbook, which BCSE has analysed in detail: The student textbook Explore Evolution describes the problem [of defining evolution] like this:…

Pp160-161: 7.1 Creation and Evolution

The teaching of creationism as an alternative to the theory of evolution constitutes one of the most controversial issues involving the new Christian schools. Walford (1995a, p20) investigated 53 of the schools in 1993 and found that the teaching of creation and evolution was one of their distinguishing features. This has been confirmed by a recent investigation involving the schools which took part in this survey, as described in Chapter 3. The Christian Schools Trust statement on the teaching of creationism and intelligent design (see Appendix 3) clarifies the approach that the majority of the schools are taking.

[Appendix 3 appended; weasel-worded, and probably best dealt with by talking about the outcomes discussed here. By their fruits shall ye know them.]

P 164: Table 7.1

Teenage pupils from new Christian schools: their beliefs about creation and evolution              Disagree/ Not sure/ Agree                                                                 %    %    %

The earth is billions of years old                                                              45   42  27

I believe God made the world in six days of 24 hours                             13   30  57

The earth is only a few thousand years old                                             34  37  39

I believe in evolution creating everything over millions of years         76   16  7

Scientists have discovered how the world was made                              67   25   8

Everything in the world was made by natural forces, not designed     71   23   5

 P 166: The schools themselves claim that, in addition to placing all of their educational practice within a Biblical creationist framework, when it comes to science education they teach creationism alongside evolution as a debate. The responses of the young people in this section go some way towards supporting this claim. A substantial majority of the young people reject the concept that living things owe their origins to a process of evolution. A smaller majority endorse the Bible‘s account of creation. However, over the question of the age of the Earth their responses are more varied and a sizeable minority indicate that they have yet to make up their minds. This indicates that questions dealing with the age of the Earth may need to be investigated more precisely and again suggests that the definitions of creationism used in this kind of research need to become yet more nuanced.

P 167: Table 7.2

Teenage pupils from new Christian schools: their beliefs about science and the Bible

Disagree Not sure Agree                                                                       %    %    %

God created the world as described in the Bible                                       6  16  78

God created the Universe including living creatures out of nothing  6   20  74

God formed man out of the dust of the Earth                                        7   22  71

God made woman out of man‘s rib                                                        8   20  72

There was once a world-wide flood as described in the Bible              4   16  81

The world was once perfect but has been affected by sin                     5   15  81

I accept the idea that living things were made by a process of evolution  67  24  10

Science disproves the Biblical account of creation                             47  34  19

You can‘t be a good scientist and believe in the Bible                       68  24  8

P 168: According to the evangelical viewpoint held by those who are running the schools, the manner of the creation of the first man and woman is of essential importance to the gospel of Jesus Christ (Cameron, 1983, pp84-91), who is described in the New Testament as the “second” or “last” Adam (1 Corinthians 15:45). Seventy-one percent of the young people in the schools claim that they believe that God formed man out of the dust of the Earth and only 7% do not believe it. Similarly, 72% believe that God made woman from Adam‘s rib, with 8% taking the opposite view. 81% of the teenagers believe that there was once a world-wide flood as described in the Bible with a tiny minority of 4% denying this, leaving 16% who are not sure about it.

 Theodicy is of central and critical importance to the creation/evolution debate and one item was included in this connection. Theodicy concerns the issue of God‘s goodness and justice in the face of the existence of suffering and evil. To the modern mind, this conundrum might appear to have nothing to do with the theory of evolution, but Cornelius Hunter has demonstrated that it is actually one of its defining concepts (Hunter, 2001). Hunter believes that Darwin was motivated towards evolution, not by direct evidence in favour of the theory but by problems with the notion of divine creation, because of how imperfect, even cruel, nature can be. “A good God would not have done it like this” is a common refrain when the subject is being debated. Creationists would argue that both suffering and death amongst animals and humans were not part of the original creation but instead are a result of “Adam‘s sin and the Edenic curse” (Tyler, 2003, p85). The great majority of the pupils, 81%, believe that the world was once perfect but has been affected by sin. Just 5% do not agree with this view and 15% have not yet decided one way or the other.

P 170: To summarise, the great majority of the young people in the new Christian schools accept a face-value reading of the early chapters of the Bible. They reject the theory of evolution and accept the existence of a supernatural designer. They hold traditional Christian views of Noah‘s flood and of the ―fallen‖ nature of the created order.

P 172: There is “science” connected with origins, much of which is historical in nature and therefore not open to what is normally regarded as the scientific method, and there is what might be summarised as “laboratory science”, where repeatable, verifiable outcomes are possible.

P 177: Table 8.1

Teenage pupils from new Christian schools: their personal well-being

                                                                  Disagree Not sure Agree  %    %    %

I feel my life has a sense of purpose                                                        4    14   83

I find life really worth living                                                                       7    19   75

I feel I am not worth much as a person                                                  68  18   14

I often feel depressed                                                                                    54  21   26

I have sometimes considered taking my own life                              71  10   19

P 179 Table 8.2

Urban Hope Survey Results: comparison by schools

Source: Francis and Robbins, 2005 pp234-236 New Christian Schools % Anglican Schools % Roman                    Catholic Schools % Non- Denom. Schools %
I feel my lifehas a sense ofpurpose 75 51 64 54
I find life reallyworth living 74 64 69 69
I often feel depressed 38 58 52 52
I feel I am notworth much asa person 12 17 13 14
I haveconsideredtaking my ownlife 15 30 26 28

[NB: New Christian School data for 2006, at height of boom; others from the depressed 1990s]

P 282: Table 11.29

Pupils compared by age: their views on education

Year 9 Year 11 Χ2 P< % %

Education is about learning facts 71 69 0.17 NS

Education is about passing exams 53 59 1.19 NS

Education is about learning how to live in a right way 68 70 0.09 NS

My schooling has helped me to know how to live in a right way 66 67 0.03 NS

Education is about understanding how to think about life 58 69 6.01 NS

Education is about understanding how other people think about life 44 61 14.16 .001

Education is about being prepared for life 80 84 0.97 NS

I want my children to go to a Christian school 70 52 15.35 .001 [Not directly relevant, but note the drop-off in wish to send one’s children to a Christian school after two more years of it. Particularly interesting in the light of the only other significant change]

P 296:Table 12.10 (Within the Christian schools)

Pupils compared by religion: their beliefs about creation and evolution

                                                                                                None      Christian      Χ2   P<  

The earth is billions of years old                                                           45       25            14.2      .001

I believe God made the world in six days of 24 hours                   21       62             49.3      .001

The earth is only a few thousand years old                                     9          43            34.2      .001

I believe in evolution creating everything over millions of years    24     5               38.8       .001

Science disproves the Biblical account of creation                            15    19      .07         NS

Table 12.11

Pupils compared by religion: their beliefs about science and the Bible

                                                                                                                      None      Christian      Χ2 P<

God created the world as described in the Bible                                              26 84 137.3      .001

God created the Universe including living creatures out of nothing       26 80 104.8      .001

God formed man out of the dust of the Earth                                                      14 79 141.0      .001

God made woman out of man‘s rib                                                                           14 80 150.7 .001

There was once a world-wide flood as described in the Bible                       24 87 172.3 .001

The world was once perfect but has been affected by sin                                24 87 170.5 .001

I accept the idea that living things were made by a process of evolution 26 7 27.2      .001

Everything in the world was made by natural forces – it was not designed 19 4 32.6      .001

Scientists have discovered how the world was made                                            16 6 11.2      .001

You can‘t be a good scientist and believe in the Bible                                            10 7 0.8      NS

Appendix 3 [to thesis]: Statement concerning:

The place of the teaching of the Creation/Evolution debate and Intelligent Design in schools affiliated to the Christian Schools Trust [2009]

[Note that this is what Dr Baker is advocating]

The Christian Schools Trust is a network of independent schools, each of which is able to subscribe to an evangelical basis of faith. The Trust is not in a position to impose stipulations on to its member schools with regard to secondary matters, nor would it wish to do so. The creation/evolution debate, although held to be very important, is regarded by the Trust as a secondary matter, which recognises that there is a diversity of views on this issue amongst Christians who hold a high view of the authority of Scripture.

The Christian Schools Trust affirms a high view of God as the Creator and sustainer of the Universe and of all living things. It categorically rejects the notion that living things have come into being by a random and purposeless process in which God has played no part. It rejects the idea that living things came about by a process involving the death and destruction of mutated creatures and affirms the belief, held by many scientists both past and present, that nature provides abundant evidence of the hand of a Designer.

The following description of how the creation/evolution issue is being approached represents the position held by many of the schools although not necessarily by all.

Teaching at Primary Level

About 50% of CST schools consist only of primary departments. The majority of the rest cover both primary and secondary levels. Young children within the schools would learn from the start of their schooling that they are created beings, that they are very valuable to God and that they are made in His image. They would be taught that He is the Creator of all things, including all living things, and that He has designed this Earth to be their home. They would also learn that creation was originally good but that it is now flawed as a consequence of sin introduced into the human race by Adam and Eve. The picture presented would be one of decline from an original state that was perfect and highly ordered. The children would be introduced to the Lord Jesus Christ as the Son of God who came to save both them and all of creation from the devastating effects of rebellion against God. [NB: this means that Adam and Eve are being taught as historical fact and as fundamental to faith, the effects of rebellion against which can be devastating]

This traditional, orthodox, Christian viewpoint, based on teaching that resonates throughout the Bible and has been preserved for millennia in creeds and catechisms, would form the framework within which all subjects, not just those related to science, would be taught. It would not be confined to RE lessons, giving the impression that it would not matter if the opposite were taught in other subjects. The schools would aim to teach consistently within this view of reality. The theory of evolution would rarely be taught directly at primary level, except to answer children‘s questions should they arise or to deal with it in immediately relevant subjects such as when fossils or dinosaurs are under consideration. The creation/evolution debate might possibly be handled in more detail with older primary children if individual schools and teachers consider it to be appropriate.


Teaching at Secondary Level

The general framework of Christian theism described above applies as much to the teaching of the older children as it does to the younger. In addition, ideally,

by the time students reach Years 10 and 11 they will have been fully exposed to the creation/evolution debate. Evidence for and against the theory of evolution will have been evaluated and discussed and they will have been made aware that many, probably [!] most, of today‘s scientists support the theory. However, it will also have been pointed out that many well-qualified scientists oppose it or dissent from it in some way. The role taken in the development of modern science by Christians such as Kepler, Boyle, Newton, Linnaeus, Faraday and Mendel will have been emphasised and it will have been noted that some of these, including Isaac Newton and Carl Linnaeus, held essentially the same position as today‘s “Young-Earth” creationists.

Students will also have been made aware of the differing positions held by Christians on this issue and may have been given an overview of both “Young-Earth” and “Old-Earth” creationist viewpoints and the theistic evolution position. By this stage, it should have been made clear to the students that creationist scientists have no quarrel with Darwin‘s theory that limited change in populations might possibly occur by a process of natural selection. They should have had the opportunity to see that this is not what the debate is about, except that most of the supposed “overwhelming evidence” for evolution falls into this uncontentious and undisputed category. The students will have been told that the debate is about the much more contentious issue, for which creationists maintain there is no convincing evidence, that there is no limit to this process and that by it all living things have come into being in a random, purposeless, fashion involving the deaths of countless billions of mutated creatures.  The creation/evolution controversy provides a stimulating, up-to-date and interesting context within which many important philosophical and scientific principles can be evaluated. Young people educated in this way do well at science both at GCSE level and beyond. Former pupils of CST schools who proceed to University are often surprised at the ignorance, on this topic, of their peers who have been educated in a secular setting which denies that the debate even exists.

Intelligent Design

The Christian Schools Trust is watching the increasing impact of the Intelligent Design Movement with interest. The fundamental premise of the movement, that biological systems show evidence of having been designed, is one that is to be predicted by those who believe in a Creator.

Darwin, Agassiz, and Global Warming; The Case of the Vanishing Lake

Darwin thought the parallel “Roads” of Glen Roy represented vanished marine shorelines, one above the other as the result of vertical movement. Agassizexplained them, rather, as successive shorelines of a glacial lake, now vanished because the retaining glacier has melted away. If so, and if global warming is real, we might expect to see vanishing lakes today, as the glaciers retreat. We can, and we do, as a recent blog post by my friend Peter Hess explains.

Glen Roy is a valley in the Western Scottish Highlands, just south of the Great Glen (home to Loch Ness), and draining through Glen Spean to Loch Linnhe, an inlet of the Atlantic. It is remarkable for the presence of the Roads, a series of parallel, almost horizontal, grooves in the hills on the sides of the glen. Clearly shorelines; but of what body of water? And why are there more than one of them?

From Darwin, C. R. 1839. Observations on the parallel roads of Glen Roy, and of other parts of Lochaber in Scotland, with an attempt to prove that they are of marine origin.  Philosophical Transactions of the Royal Society 129: 39-81, through Darwin Online

Charles Darwin visited the area in 1838, two years after his return from his round the world voyage on the Beagle. During that voyage, he had examined the geology as well as the plants and animals of the places he visited, and among them was the coastal area of Chile. This is marked by raised beaches inland where once had been shoreline, and Darwin correctly described these as the effects of uplift, which we now know to be driven by plate tectonics. So it was natural thatDarwin should have applied a similar explanation to the Roads, suggesting that the Cairngorms, like the Andes, were a zone of uplift, and that the Roads were ancient beaches of the Atlantic, now some ten miles away. The alternative theory, that they represented shorelines of an ancient lake, ran up against a seemingly conclusive objection; such a lake could only have formed if there had been a barrier across the valley, but there was no trace of this.Only a year later, shortly after going public with his Ice Age theory, the naturalist Louis Agassiz visited the area. In the Highlands he found plenty of evidence to support his idea; scratches on bedrock caused by the passage of glaciers, erratics (boulders far from their parent rock formations), and moraines (piles of rock rubble that had been carried by glaciers, left in place when the glacier melted). He considered the Roads further evidence of this; yes, there had been a lake, and yes, the roads did represent the shorelines at different times, carved into the sides of the valley by fierce freeze-thaw cycles. As for the barriers holding the lake in place at different levels over the course of time, they were a series of long vanished glaciers.

We now know that Agassiz was basically correct, although we now speak of a series of glaciations rather than a single Ice Age, and although Darwin was right in this; that the area has in addition experienced uplift, as the weight of ice above it has melted away.

Later Darwin was to write of this as his greatest blunder, describing in his Autobiography how in Wales he had missed the evidence of glaciation all around him, and generously acknowledging Agassiz for having come up with the correct explanation.

Agassiz rejected Darwin’s concept of evolution when it was published twenty years later because he believed in the fixity of species, but this does not seem to have diminished Darwin’s respect for him. What is now nothing but a deliberately cultivated ignorance was then, with so much less evidence available, no more than an understandable conservatism.

The overflow channel through which the vanished Loch Roy must have drained can still be detected as an abrupt narrow valley in the surrounding hillsides. The draining of the vanished lake in South America sent a surge through its own channel, down Chile’s main river, and caused giant waves as far as the Pacific Ocean, 60 miles away.

Lake to sandy valley overnight (from Peter Hess posting on NCSE blog site)

The glaciers of Switzerland are receding. Those of the southern Andes are receding even faster. Since Agassiz and Darwin examine the roads of Glen Roy, the earth’s mean surface temperature has increased by roughly 1oC, with another 0.5oC in the pipeline even if emissions were to be stabilised at the same levels as in the year 2000.

Which, of course, they won’t be.

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