What makes a hypothesis scientific, vs a just-so story, or a religious fixation?
"Intelligent" design has fallen on hard times, after a series of court cases determined that it was, after all, a religious idea and could not be foisted on unsuspecting schoolchildren, at least in state schools and under state curricula. But the very fact of religious motivation leads to its persistence in the face of derision, evidence, and apathy. The Discovery Institute, (which, paranthetically, does not make any discoveries), remains the vanguard of intelligent design, promoting "skepticism", god, alternative evolutionary theories, and, due to the paucity of ways to attack evolution, tangential right-wingery such as anti-vaccine agitation. By far their most interesting author is Günter Bechly, who delves into the paleontological record to heap scorn on other paleontologists and thereby make room for the unmentioned alternative hypothesis ... which is god.
A recent post discussed the twists and turns of ichthyosaur evolution. Or should we say biological change through time, with unknown causes? Ichthyosaurs flourished from about 250 million years ago (mya) to 100 mya, with the last representatives dated to 90 mya. They were the reptile analogs of whales and dophins, functioning as apex predators in the ocean. They were done in by various climate crises well-prior to the cometary impact that ended the Cretaceous and the reign of dinosaurs in general.
Bechly raises two significant points. First is the uncertain origins of Ichthyosaurs. As is typical with dramatic evolutionary transitions like that from land to water in whales, the time line is compressed, since there are a lot of adaptations that are desirable for the new environment that might have been partially pre-figured, but get fleshed out extensively with the new ecological role and lifestyle. Selection is presumably intense and transitional fossils are hard to find. This was true for whales, though beautiful transitional fossils have been found more recently. And apparently this is true for the Ichthyosaurs as well, where none have been found, yet. There is added drama stemming from the time of origin, which is right after the Permian exinction, perhaps the greatest known extinction event in the history of the biosphere. Radiations after significant extinction events tend to be rapid, with few transitional fossils, for the same reason of new niches opening and selection operating rapidly.
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| Ichthyosaur |
Bechly and colleagues frequently make hay out of gaps in the fossil record, arguing that something (we decline to be more specific!) else needs to be invoked to explain such lack of evidence. It is a classic god of the gaps argument. But since the fossils are never out of sequence, and we are always looking at millions of years of time going by with even the slimmest layers of rock, this is hardly a compelling argument. One thing that we learned from Darwin's finches, and the whole argument around punctuated equilibrium, is that evolution is typically slow because selection is typically not directional but conservative. But when selection is directional, evolution by natural selection can be startlingly fast. This is an argument made very explicitly by Darwin through his lengthy discussions of domestic species, whose changes are, in geological terms, instant.
But Bechly makes an additional interesting argument- that a specific hypothesis made about ichthyosaurs is a just-so story, a sort of hypothesis that evolutionary biologists are very prone to make. Quite a few fossils have been found of ichthyosaurs giving birth, and many of them find that the baby comes out not only live (not as an egg, as is usual with reptiles), but tail-first. Thus some scientists have made the argument that each are adaptations to aquatic birth, allowing the baby to be fully borne before starting to breathe. Yet Bechly cites a more recent scientific review of the fossil record that observes that tail-first birth is far from universal, and does not follow any particular phylogenetic pattern, suggesting that it is far from necessary for aquatic birth, and thus is unlikely to be, to any significant extent, an adaptation.
Ha! Just another story of scientists making up fairy tales and passing them off as "science" and "evolutionary hypotheses", right?
"Evolutionary biology again and again proves to be an enterprise in imaginative story-telling rather than hard science. But when intelligent design theorists question the Darwinist paradigm based on empirical data and a rational inference to the best explanation, they are accused of being science deniers. Which science?" ... "And we will not let Darwinists get away with a dishonest appeal to the progress of science when they simply rewrite their stories every time conflicting evidence can no longer be denied."
Well, that certainly is a damning indictment. Trial and sentencing to follow! But let's think a little more about what makes an explanation and a hypothesis, on the scientific, that is to say, empirical, level. Hypotheses are always speculative. That is the whole point. They try to connect observations with some rational or empirically supported underlying mechanism / process to account for (that is, explain) what is observed. Thus the idea that aquatic birth presents a problem for mammals who have to breathe represents a reasonable subject for an hypothesis. Whether headfirst or tailfirst, the baby needs to get to the surface post haste, as soon as its breathing reflex kicks in. While the direction of birth doesn't seem to the uninitiated (and now, apparently to experts with further data at hand) to make much difference, thinking it does is a reasonable hypothesis, based on obvious geometric arguments and biological assumptions, that it is possible that the breathing reflex is tied to emergence of the head during birth, in which case coming out tailfirst might delay slightly the time it takes between needing to breathe and being able to breathe.
This argument combines a lot of known factors- the geometry of birth, the necessity of breathing, the phenomenon of the breathing reflex initiating in all mammals very soon after birth, by mechanisms that doubtless are not entirely known, but at the same time clearly the subject of evolutionary tuning. And also the paleontological record. Good or bad, the hypothesis is based on empirical data. What characterizes science is that it follows a disciplined road from one empirically supported milestone to the next, using hypotheses about underlying mechanisms, whether visible or not, which abide by all the known/empirical mechanisms. Magic is only allowed if you know what is going on behind the curtain. Unknown mechanisms can be invoked, but then immediately become subjects of further investigation, not of protective adulation and blind worship.
In contrast, the intelligent design hypothesis, implicit here but clear enough, is singularly lacking in any data at all. It is not founded on anything other than the sentiment that what has clearly happened over the long course of the fossil record operates by unknown mechanisms, by god operating pervasively to carry out the entire program of biological evolution, not by natural selection (a visible and documented natural process) but by something else, which its proponents have never been able to demonstrate in the least degree, on short time scales or long. Faith does not, on its own, warrant novel empirical mechanisms, and nor does skeptical disbelief warrant them. Nor does one poor, but properly founded, hypothesis that is later superceded by more careful analysis of the data impugn the process of science generally or the style of evolutionary thinking specifically.
Imagine, for example, if our justice system operated at this intellectual level. When investigating crimes, police could say that, if the causes were not immediately obvious, an unnamed intelligent designer was responsible, and leave it there. No cold cases, no presumption of usual natural causality, no dogged pursuit of "the truth" by telegenic detectives. Faith alone would furnish the knowledge that the author of all has (inscrutibly) rendered "his" judgement. It would surely be a convenient out for an over-burdened and under-educated police force!
Evolution by natural selection requires a huge amount of extrapolation from what we know about short time scales and existing biology to the billions of years of life that preceeded us. On the other hand, intelligent design requires extrapolation from nothing at all- from the incredibly persistent belief in god, religion, and the rest of the theological ball of wax not one element of which has ever been pinned down to an empirical fact. Believers take the opposite view solely because religious propaganda has ceaselessly drilled the idea that god is real and "omnipotent" and all-good, and whatever else wonderful, as a matter of faith. With this kind of training, then yes, "intelligent" design makes all kinds of sense. Otherwise not. Charles Darwin's original hypothesis was so brilliant because it drew on known facts and mechanisms to account (with suitable imagination and extrapolation) for the heretofore mysterious history of biology, with its painfully slow yet inexorable evolution from one species to another, one epoch to another. Denying that one has that imagination is a statement about one's intelligence, no matter how it was designed.
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