Was Hypatia of Alexandria a Scientist?

a film review by S. James Killings

THE FILM AGORA, RELEASED IN THEATRES IN LATE 2009 in Spain and this summer in the United States, portrays an unlikely heroine for the popular American audience — the ancient mathematician Hypatia of Alexandria, played by Rachel Weisz. Although renowned as a Neo-Platonic philosopher during her lifetime, she is remembered more often for her death than for her life. In 415 AD the pagan Hypatia was caught up in the political and religious violence that routinely swept Alexandria and murdered by a group of fanatical Christian monks who were intent on making an example of her. One of her colleagues, the Syrian Damascius, placed the blame squarely on the Patriarch Cyril of Alexandria and his Christian followers.

In the 18th century, the Enlightenment thinkers John Toland and particularly Voltaire seized on Damascius’ story of Hypatia’s death as symbolic of the antagonistic nature the Christian religion had toward the freedom of inquiry. They imagined her as a martyred symbol of free thought who was destroyed by the irrational dogmas of the growing ecclesiastical patriarchy. Her death, according to her blossoming legend, set back free inquiry a thousand years and ended the scientific hopes of the Hellenistic Age. This image of Hypatia as an Enlightenment symbol was to have far-reaching influence well into the 20th century, as Maria Dzielska explains in her book, Hypatia of Alexandria, so much so that it has become difficult now to untangle the historical Hypatia from her literary legend. Amenábar’s Hypatia, also apparently influenced by Carl Sagan’s portrayal of her in his documentary film Cosmos, appears to be another cultural product of this Enlightenment legend.

The intersections of religion and science and rising concerns over religious fundamentalism have gripped the news in recent years, so it is no wonder Amenábar has resurrected Voltaire’s Enlightenment emblem again. But Hypatia’s portrayal as scientific heroine in the movie deserves some scrutiny not the least to separate her legend from history for those who have not studied ancient philosophy, but also to give credit where credit is due for the advancement of scientific reasoning.

The historical life of Hypatia is shrouded in the mists of the past. She was the daughter of the mathematician Theon, who was known to have been associated with the Museion of Alexandria in the 4th century. What we know of her mathematical work (and much of her life) comes from a Byzantine history, the Suda, compiled five centuries after her death. She is thought to have written commentaries on the conics of Apollonius and the Arithmetica of Diophantus, along with an introduction to astronomical treatises, none of which have survived. It has been argued that she contributed a not insignificant part to her father’s editions of Euclid and Ptolemy, and perhaps all of her commentaries were collaborations with her father. She taught at the Neo-Platonic School in Alexandria, an institution separate from the Museion. As a teacher of Plato and Aristotle, according to the Suda, she became famous throughout Alexandria. She has often been associated with the invention of the hydrometer, a tool used to measure the density of liquids, but the wording of the evidence — Synesius of Cyrene’s letter to her — casts doubt on that score.

Although we cannot be completely certain of the nature of Hypatia’s mathematical work, the commentaries and work attributed to her in the Suda do suggest that she was interested in astronomy. Apollonius described the eccentric movements of the planets, their epicycles and deferents and described the mathematical properties of the ellipse, hyperbola and parabola. Ptolemy builds on Apollonius’ work to construct his geocentric model of the planets. Diophantus’ Arithmetica provides examples of quadratic equations that are necessary to determine the properties of curves. Because of her association with the Neo-Platonic school in the 4th century Near-East, her work may have had something to do with the Plotine criticism of astrology. Plotinus, the founder of the Neo-Platonic school, was highly skeptical of astrological divination, and so we would expect was Hypatia.

Confused by the irrational properties given by astrologers to this or that planet as it moved through the Zodiac, Plotinus asked: “What is the comprehensive principle of coordination [of the movements of the planets]? Establish this and we have a reasonable basis for divination.…” Plotinus believed the planets were living beings that paradoxically had no will but were bound to follow a set course through the heavens. In her studies of conics and curves, Hypatia may have thought to determine the “comprehensive principle of coordination” of these heavenly beings in order to make divination more rational. We may never know. But of the Neo-Platonists of her era — Porphyry, Iamblichus, Proclus, Damascius — Hypatia appears to have been unique in her focus on astronomy and this may have contributed to her popularity (and animosity toward her) in the superstitious culture of Egyptian Alexandria.

The scientific subplot of the movie has Hypatia questioning the geocentric theory of the planets as espoused by Aristotle and then Ptolemy. Amenábar’s Hypatia engages in physics and mathematics in her pursuit. Her empirical experiment with the falling grain sack aboard the ship proves that gravity has the same effect on falling objects whether moving forward or standing still. She excitedly concludes that the Earth could be moving forward in the heavens and we could be unaware of it (the logic of her conclusion is not explained in the film). This notion of a moving, non-stationary Earth, is in contravention to the Aristotelian idea of gravity which held that earth, as one of the four elements, was drawn to its natural place at the centre of the spherical universe, which also comprised the other three elements, water, air and lastly fire. Nonetheless, her experiment aboard the ship opens her up to questioning Ptolemy’s geocentric planetary model of celestial spheres and epicycles. Using her knowledge of Apollonian conics, mathematics, and a clinometer, she at length correctly deduces the elliptical orbits of the planets (Kepler’s first law of planetary motion) in a helio-centric (Copernican) system, a pair of discoveries that would have been 1200 years before their time.

The kind of reasoning that Amenábar’s Hypatia engages in, with the falling grain sack and the theoretical knowledge drawn from observation and experiment, is known as empiricism. It is a logical method so fundamental to our modern approach to science, especially astronomy, that it is difficult, if not impossible, for us to comprehend any useful scientific enterprise without it. But empiricism is the product of a long history of philosophers beginning principally with Avicenna in the 11th century and practiced by the likes of Tycho Brahe and Johannes Kepler in the cause of astronomy in the 16th century. It was developed into a philosophical practice through the Enlightenment principally by John Locke and David Hume. This mode of thought would have been completely alien to the real Hypatia of Alexandria, not because her mind was not equipped for such paths, but because she, her colleagues, her father, and their predecessors had no experience in nor knowledge of such logical methods. Moreover, as a 4th century Platonist, Hypatia likely mistrusted physical observation altogether and believed, like her mentor Plotinus, that she could uncover the mysteries of the universe by ratiocination alone.

The story of her menstrual rags in the Suda was meant to illustrate this point: as a female philosopher, Hypatia was not interested in the physical, only the metaphysical. To employ empiricism to call into question Aristotle she would have had to first call into question her entire metaphysical philosophical tradition and invent almost ex nihilo a whole new and mature method of reasoning. In other words, the real Hypatia would have been more likely to attribute the physical properties of the falling grain sack to the god Seraphis, than to the possibility that it meant the Earth was moving in the heavens in contradiction to Aristotle. She simply had no body of evidence nor rational means to conclude otherwise. It would take another millennia and considerable advances in other scientific areas — especially in logic, argumentation, mathematics, instrumentation and observation — before thinkers could begin to accurately describe the motions of the planets and the workings of the heavens.

Without these logical methods and evidence, and as a Neo-Platonist, Hypatia’s astronomical study of conics and curves would have been a purely philosophical and mathematical pursuit, exercised in the cloistered confines of the Alexandrian Library, divorced from empirical observation. Nowadays, it is strange to contemplate astronomy without empiricism, but the Platonic philosopher Hypatia would have reveled in it. If we must give her a modern scientific title by which she can be recognized, it would be more accurate to describe her as a mathematician in the purest sense.

We ought not to diminish nor elevate Hypatia’s contribution to science. Making too much of her legend does great disservice to the multitude of men and women throughout history who have made modern science possible. If any great credit is due to the advancement of scientific reasoning and the birth of the Modern Age it is not to a rediscovered Hypatia, but to the many thinkers and philosophers of the Renaissance and Enlightenment who, after more than two millennia, first put into words and practice a revolution in our understanding of the universe. Amenábar has seemingly made Hypatia into a symbol of the modern scientific method. Voltaire would have approved.

Waterworld
A review of The Flooded Earth:
Our Future in a World Without Ice Caps

review by James N. Gardner

IS ANTHROPOGENIC GLOBAL WARMING the cataclysmic threat that Al Gore and the United Nation’s Intergovernmental Panel on Climate Change proclaim it to be? Or do powerful natural forces like variable solar output, plate tectonics, and volcanic activity dwarf the climate impact of human-generated greenhouse gases?

That is the deep question that lurks beneath the surface of a fascinating new book — The Flooded Earth: Our Future in a World Without Ice Caps — by University of Washington scientist Peter D. Ward. Ward, co-author of the highly acclaimed Rare Earth: Why Complex Life Is Uncommon in the Universe, is at his best when he provides snapshots of the climate extremes our planet has experienced over the billions of years of its existence. Here is his description of ancient episodes of global warming that make the dire warnings of current climate prognosticators seem almost benign:

Long before humans were even a gleam in nature’s eye, the convergence of geological forces repeatedly caused the planet to heat up. Such events, however rare, hugely altered life and its evolution. The warming had resulted from enormous volumes of carbon dioxide that emanated from the flood basalts, creating atmospheric greenhouse conditions that quickly heated the planet to a point that the poles were nearly as warm as the equator, leading the normal winds and ocean currents to diminish and in some cases totally stop. A stilled ocean, eventually even on its surface regions, loses oxygen. The apparent result was a series of nasty events, such as oceanwide “dead zones” … where conditions of eutrophication — where a body of water first warms and then loses its oxygen as its enclosed life dies and then rots — have eliminated all the life-giving oxygen in the water.

If nature is capable of this level of environmental catastrophe on its own, just how much can we feeble humans really influence the future evolution of the vast, complex global climate system? The optimistic answer, favored by Ward, is that humankind is now firmly in the driver’s seat of climate change:

As I give talks around the country about a newly discovered phenomenon of the deep past greenhouse extinctions, people always ask about the relevance of these studies to the present and near future. That question is simple to answer, at least for me: what happened in the past can and will happen again if we continue to heat the planet at present rates.

Ward’s implication is that if we humans will only cease our global warming malefactions, the violent climatic oscillations he so colorfully documents — oscillations that predate by millions of years humanity’s evolutionary emergence on the savannahs of Africa — will be brought under tolerable control.

The pessimist would argue that the mountain of geological evidence assembled and expertly presented by Ward points to precisely the opposite conclusion — that what happened in the past can and will happen again regardless of what human beings do.

What seems incontrovertible from Ward’s compelling narrative is that, irrespective of the precise causal interplay of human-induced and natural factors, the Earth’s deep history offers ample evidence that the atmospheric conditions on this planet are likely to continue to fluctuate dramatically, with potentially dire consequences for the biosphere. From the mysterious Permian extinction 250 million years ago, in which 96% of all marine species went extinct, to the Cretaceous-Tertiary extinction event 65 million years which killed off the dinosaurs, the story of our planet’s long environmental history is a tale of repeated episodes of dramatic change that have threatened the very survival of complex life.

In the face of this overwhelming evidentiary record, only a cock-eyed optimist would contend that what is past is not prologue.

How Much Does Being Right Matter?

by Dr. David H. Voelker

THE MARKET FOR BOOKS about how ordinary people make thinking mistakes being fairly saturated (Predictably Irrational, Sway, Nudge), it makes sense that someone would turn the spotlight on a group that’s supposed to mess up less than the rest: experts. Journalist David Freedman walks us through an impressive list of false and conflicting claims made by experts in a variety of fields that really drives home the dubiousness of much — if not most — of what passes for expert wisdom. The book is worth this carefully assembled and annotated collection of dueling truth claims alone.

There’s plenty of blame for our expert misinformation to go around, says Freedman. From respected scientists to financial wizards to self-appointed relationship gurus, people whom we credit with specialized knowledge conduct sloppy research, suppress disconfirming data, and leap to unwarranted conclusions. Journalists oversimplify and misrepresent study findings. Bad advice thrives in part because the public demands easy fixes that are “resonant, provocative and colorful.”

We would expect Wrong to cover famous cases of expert fraud like the South Korean human embryo cloning scandal, and it does. Most of the expert errors documented here, however, are not intentional, but originate in the cognitive biases to which everyone is prone. Like the rest of us, experts have sharper eyes for data that supports their hypotheses, claim to have started out looking for what they eventually found, and play to their employers’ metrics (research funding agencies). Nor are peer review and other forms of self-regulation much of a remedy: Thomas Kuhn showed some fifty years ago how the practices of scientific communities reinforce and perpetuate prevailing paradigms.

It would be unremarkable to learn that experts sometimes make mistakes, but if Wrong is right, the magnitude of the problem is much greater than most people suspect. The findings of two out of every three published medical studies fail to hold up. When you consider that the truth claims of less highly-educated and credentialed experts like the inventor of the latest diet or management fad are on average even less reliable, you realize we’re awash in untrustworthy advice.

Books written to hammer a single point are vulnerable to overstating their case, and Freedman’s expert targets are sometimes damned if they do and damned if they don’t. For example, he criticizes mainstream scientific research for careless procedures and small, unrepresentative samples but later defends junk science because, even though its procedural rigor and signal to noise ratio are typically even lower, it occasionally stumbles upon a nugget missed by the pros. That’s having it both ways. Similarly, he fails to take his own advice against retrospective sense-making when he says the warning signs in a famous case of scientific fraud were “glaringly obvious” when looked back upon.

Freedman knows his task leaves him open to the charge of begging the question: the same lack of certainty he says accompanies expert judgments must also apply to his own assumptions that particular expert claims are wrong. I agree with his defense that, though any individual claim may be mistaken, accumulating and pooling evidence allows us to converge on the truth. A historical progression of geographic maps provides an example: early maps of the world are wildly discrepant, but the shapes of the continents and details in their coastlines gradually converge and stabilize across cartographers over time.

So common are the serious errors catalogued in Wrong by even the most eminent researchers and institutions, though, and so influential are false claims in directing the flow of dollars and in propping up whole industries and reputations, that by the time you reach the simple guidelines at the end of the book for knowing when to suspect that an expert opinion might be wrong, it feels the equivalent of being advised to move a foot inland from the beach to protect against tsunamis.

Wrong’s abundant examples of how experts fail us demonstrate how complex the world is. The contingencies of cause-and-effect relationships can be many and difficult to trace, and good advice in one situation can lead to disastrous results in another.

Unfortunately, directing experts (or the middlemen who report their work) to qualify their truth claims with all of the ways they could be wrong, and publicizing negative findings as well as positive ones, are no solution. That just adds to the pile of stuff we have to sift through, and makes it harder for our brains to fulfill what is perhaps their most important function, and is the main reason we rely on experts in the first place: information reduction; sorting through the noise for the signal. The best we can hope to do (whether expert or layman) is narrow the confidence intervals of our predictions a little, and be wrong a little less often.

On the surface, Wrong is about the untrustworthiness of expert advice, but it has much deeper implications. As William James observed a century ago: “Truth lives, in fact, for the most part on a credit system. Our thoughts and beliefs ‘pass,’ so long as nothing challenges them, just as bank-notes pass so long as nobody refuses them.”

Even though experts might eventually converge on the truth about specific clearly defined causal relationships, across the multitude of main effects and complex interactions that each of us experiences in a typical lifetime, the saying, “the truth will out,” is false. At any given time, a substantial number of our individual and shared beliefs about the causes of those effects are simply wrong. We’re guaranteed to take to our graves false conclusions about why this diet did or didn’t work for us, why that relationship went sour, or whether our grown child wouldn’t have committed spousal abuse if only we’d spared the rod.

The degree to which the truth doesn’t “out” is the latitude that experts — and anyone, for that matter — have to construct social realities with impunity. For the objectively false claims described in Wrong and others we hear every day to have the power they do to launch movements, sell products, determine government policy and distribute social rewards, being right doesn’t matter as much as being accepted.

That, I think, is the real lesson of Wrong.

If you don’t understand evolutionary biology, don’t write a book about it!

by Donald R. Prothero

THE DARWIN CELEBRATIONS OF 2009 led to a glut of books about evolution, which took a wide variety of approaches. Most books were written by biologists, paleontologists, or historians trained in the subject; others were written by the creationists trying to counter all the Darwin publicity. Yet there are books that fall into neither of these categories. What Darwin Got Wrong by Jerry Fodor and Massimo Piatelli-Palmarini (abbreviated FPP hereafter) is a wrongheaded effort by a philosopher and a cognitive scientist (neither of whom has any firsthand research experience relevant to evolutionary biology) to critique natural selection.

The confusion begins with the title. The authors state up front that they are both atheists, accept the fact that life has evolved, and do not agree with creationism or “intelligent design”—yet they used a title that is bound to boost sales by giving creationists the impression that this is a serious scientific critique of evolutionary biology. In particular, the use of Darwin’s name in the title (talking about “Darwinism” rather than modern evolutionary biology, or even 1950s-style “Neo-Darwinism”) is a classic creationist tactic. In fact, modern evolutionary biology only vaguely resembles what Darwin thought 150 years ago. So what if Darwin got a few things wrong? We’ve learned a lot in the past century and a half! What is remarkable is how much Darwin got right despite the fact that he knew nothing about genetics, and very little about the fossil record. Throughout the book, FPP resurrect some of the hoariest discredited creationist arguments (such as “natural selection is tautological”), showing that they have not only failed to acquire any relevant training in evolutionary biology, but also have not understood the standard responses to these creationist canards.

Since FPP don’t deny that life has evolved, or that all life is related by a patterns of ancestry and descent (the chief issue that bothers creationists), FPP’s entire convoluted argument is against Darwin’s main mechanism for evolution, natural selection. There are some evolutionary biologists who have argued that natural selection is not the exclusive explanation for all aspects of life’s evolution, from Stuart Kauffman’s emphasis on natural self-organizing systems, to Stephen Jay Gould’s push to recognize contingency and hierarchy in evolutionary biology. But none of these scientists questions the idea that natural selection is real, or that it has a very important role to play in the evolution of new species. FPP review many of the recent developments in evolutionary biology, from neutralism to group selection to self-organizing systems to jumping genes to evo-devo. These important scientific discoveries have certainly broadened our understanding of how evolution works, but none of the people who made these discoveries doubt that natural selection still plays an important role in the process of evolution.

In effect, what FPP are suggesting is that each time we learn more about the evolutionary process, all of what we knew before must have been wrong! There are some instances (known as “scientific revolutions”) where scientific discoveries have radically changed the foundation of a field and thrown out the entire paradigm, but none of the examples the FPP discuss are of that nature. They are simply challenges to a narrow and restrictive form of Neo-Darwinism, not to the basic premise that natural selection is a very important (if not the most important) component of evolutionary change.

Much of the book consists of beating dead horses and straw men as if biology has learned nothing since the 1950s. FPP talk about gene linkages and “free rides” of one gene upon another, about the laws of form and Fibonacci series in organisms, and about endogenous factors affecting form and development despite the fact that biologists have been working hard for many years to understand and explain these phenomena. If FPP bothered to read any of the recent literature on these subjects over the past 30 years, they would have found that these phenomena are pretty well understood. They do not force us to throw out the baby of natural selection with the bathwater of the failed ideas that evolutionary biology has rejected.

To FPP, the fundamental problem is this: how do we decide which features are selected for, and which ones are “free riders” invisible to natural selection? In their approach, if most of evolution is about “free riders” that are not selected for or against, then natural selection is irrelevant. They discuss the classic 1979 paper by Stephen Jay Gould and Richard Lewontin, “The Spandrels of San Marco: A Critique of the Adaptationist Programme.” In that paper, Gould and Lewontin were criticizing the then-prevalent naïve form of extreme panselectionism in which every tiny aspect of an organism was presumed to be subject to natural selection in some way, even if we can’t detect it. Gould and Lewontin rightly pointed out that (like the spandrels which are functional byproducts of two arches meeting), many features of organisms are due to structural or functional constraints, and we should not assume that such features are fine-tuned by natural selection. Most evolutionary biologists have taken the Gould and Lewontin (1979) paper in the spirit in which it was intended, and there is plenty of research now into functional/ structural constraints. When I attend professional meetings, I find very little of the naïve panselectionism that I encountered in my evolution classes and textbooks of the 1970s.

Yet FPP take the Gould/Lewontin critique too far, and make the absurd claim that because some features are possibly constrained and not fine-tuned by natural selection, we cannot assume that natural selection works anywhere. What about all those studies that demonstrate tight correlations of cause and effect between a feature and the selective response that occurs when nature intervenes? According to FPP, these are not conclusive enough. Therefore, whenever we have a large data set that shows a strong correlation between say, obesity and heart disease, or increases in carbon dioxide and global warming, we cannot even begin to suggest that there might be a causal connection. If this is the angle that FPP are pushing, then they have a dispute with almost all of science, not just evolutionary biology.

Their claim is that if we see an apparent feature of an organism, and then determine what natural selection does to organisms which possess this feature, we cannot rule out the possibility that there was some unknown, invisible characteristic of the organism that caused differential survival, rather than the obvious conclusion that it was due to natural selection on the features we can study. This is false on several counts. First of all, there are many experiments (not acknowledged by FPP) that have done careful work with controls and minimizing the variables that conclusively show natural selection to be the only reasonable explanation for the results. And secondly, what are these alleged “invisible forces” that might explain survival better than natural selection? How the heck do we evaluate them? In FPP’s view, natural selection is a fine-tuned discriminator that can tell the difference between all these arbitrary categories that philosophers with no experience in biology can imagine. In reality, natural selection is a coarse filter. Some features of an organism appear to make a difference, and others are indeed free riders. But the overwhelming evidence of 30 years’ worth of natural and laboratory experiments show that natural selection indeed works, and there is no practical reason to worry about “invisible” (and untestable) causes when a clear cause-and-effect chain has been established.

If you found the previous discussion confusing and hard to follow, it is no accident. The thinking and writing of FPP are so muddled and verbose and confusing that most people (including most evolutionary biologists who reviewed it) couldn’t make much sense of the book, either. In fact, FPP raise points that amount to philosophical hair-splitting and make no real difference to practicing biologists.

There are many instances of where philosophers can contribute insights to the activities of others. But in the philosophy of science, it is much trickier. Some philosophers have built whole careers out of trying to explain what scientists should do, without any regard to the reality of what scientists actually do. Yet scientists keep on making big discoveries and changing our world, oblivious to philosophers who waste time arguing about idealized views of science. Here we see another examples of outsiders like FPP who would be well advised to spend some time doing real evolutionary biology, and becoming familiar with the recent research and debates, instead of beating dead horses (such as 1960s–1970s panselectionism) and strawmen arguments from 40 years ago.

Even more annoying is the fact that FPP don’t give evolutionary biologists much credit for understanding what they do, modifying their approaches as new fields such as evo-devo have appeared, and being careful and self-critical not to overextend their conclusions. Most biologists are very cautious about asserting cause and effect relationships between some feature and natural selection unless they have done all the necessary controls and dealt with all the variables; otherwise, their work would not pass peer review and be published. As their confusion and errors clearly demonstrate, FPP are outsiders with a distorted, mistaken view of the entire field who don’t understand the field well enough to level valid criticisms. When they have done their homework and acquired the relevant training, then the evolutionary biology community might take them seriously.

Macroevolution & Microcreationism
Another Flaw in Intelligent Design Creationism

by David Eller

A STANDARD TACTIC USED by creationists to attack evolution is to contrast microevolution (i.e., within species evolution, which they accept) with macroevolution (i.e., between species evolution, which they adamantly reject). Microevolution, they grant, may or does occur. But they assert that macroevolution either has never been observed or is theoretically impossible. They argue that while microevolution may be true, it is trivial, and the major claim of evolution — the evolution and emergence of species — is either unsubstantiated or false.

This failure to account for macrophenomena, such as human life, the earth, or the universe, then serves as an opportunity to suggest that creation is the only plausible alternative for the origin of life. This conclusion suffers from the fallacy of the excluded middle or false dilemma (just because B is false does not make A true). But ironically the “success” of the “scientific” creationist enterprise, particularly its most recent and “serious” incarnation — Intelligent Design (ID) — has itself up to this point rested on claims regarding a few minor fragmentary subspecies processes rather than the macroprocesses that it is so keen to deny to evolution.

I argue in this article that creationism faces its own micro/macro distinction and challenge, and that ID has so far only focused on and made claims about microprocesses. Finally, I posit that whatever achievements microcreation may have made or may have imagined it made, these achievements neither strengthen the case for macrocreation nor weaken the case for macroevolution.

Microevolution and Macrocreation

The modern synthesis of evolutionary theory aims to be a “complete” theory. It postulates processes that function at the subspecies as well as the species levels and uniformly throughout the living world. The details may vary , but biochemical systems, species, and living systems as a whole evolve by way of natural processes. Finally, most if not all of these processes — mutation, natural selection, genetic drift, symbiosis, etc. — have been identified and described.

Even within evolutionary theory the distinction between “micro” changes and “macro” changes is widely accepted. In the simplest sense, microevolution is modification within a species. It is the (relatively) minor variation or development that leads to, say, different colors of a species of moth or different strains of a species of bacteria. Darwin himself said as much when he described “descent with modification” as the gradual accumulation of novelty and diversity. Prior to passing a “critical mass” of accumulated modification, evolution will be intraspecies. However, at a certain point, a threshold would be crossed, and the accumulated novelty would result in a transition between species, the emergence of a new species out of an old one — that is, speciation. Even more, at a still higher level, a threshold would have to be crossed to move from an entire order or class or ultimately kingdom of species: at some point, primates must diverge from mammals, mammals from reptiles, and even animals from plants. Granted, this accomplishment would take many, many generations, so we would not expect to observe it happening before our eyes, unlike microevolution, which is often observable over a few generations of a species and within the lifetime of a human observer. Still, if macroevolution actually occurs, it ought to leave some traces, particularly “transitional forms,” that link primates to other mammals, mammals to reptiles, and animals to plants.

Creationism is more difficult to pin down, since there are so many differing and even conflicting versions of it. Some claim that one or more supernatural beings brought all of the variety of the universe into existence at one time with a word or thought. Others claim that creation has been a more “ongoing” phenomenon, with a creator working through physical or natural processes to achieve the conditions existing today. Some think it was all a recent accomplishment, some an ancient one. Some assert specific knowledge of the creation, others offer only the suggestion that there is/was a creation. No matter what the details, creationism also purports to be a complete explanation. In fact, whether or not it purports to be, it is obligated to be, since no theory can leave key facts and processes unaccounted for.

Of the available creationisms, the one that most seeks and claims scientific respectability is ID. It consists of an assortment of scholarly activities, some “logical” or polemical (essentially, trying to discredit evolutionary theory) and some “empirical” or evidential. Among the evidential work of the movement, perhaps Michael Behe’s Darwin’s Black Box¹ best represents what “creation science” looks like. In this book, Behe describes, in fairly technical terminology, certain biological systems, including the flagella of protists, the human eye, and the blood-clotting system, and argues that they reveal an extremely ordered and “purposive” nature. Each system is assembled from myriad parts that individually would have no useful function but which, together in specific ways, have an invaluable function. Thus, these systems evince an “irreducible complexity” that did not (and could not) evolve unintentionally. The parts of the system had to have been purposefully, that is intelligently, designed with their end — their combination and function — in mind.

Behe’s work, and, as far as I know, the subsequent work of ID, does not make any explicit empirical claims about large-scale design. For instance, Behe certainly does not claim in Darwin’s Black Box that humans were intelligently designed or that the Earth or the Universe was so designed. There are, of course, other researchers at work, some associated with the ID movement, who attempt to extend the design notion. Those who advance the “anthropic principle,”² especially in its “strong version,” insist that the universe itself shows such complex, unlikely, and purposive qualities that it must have been designed by some non-immanent intelligence as well. This would definitely constitute a “macrocreationist” view. A scientific creationist account of the appearance of the human species or of any (and all) other species would also necessarily be macrocreationism.

However, Behe and most of the effort of the ID movement is not directed at this level or about these questions. They focus on subspecies, microlevel phenomena, like flagella and eyes. Such explanations constitute a kind of microcreationism — claims about how lower-level, intraspecies systems or parts of systems came into being. Microcreation, then, is entirely comparable to microevolution. But neither is a sufficient theory by itself. Evolution demands macroevolution and creationism demands macrocreationism.

Before we proceed to ask whether microcreation supports macrocreation (and refutes macroevolution), let us ask another question: since creationism of whatever sort intends to displace and supercede evolution, why would it give credence to microevolution, which might provide grounds for macroevolution? Why tolerate any level of evolution? One possible answer is that ID creationists see microevolution as no threat to their program. As long as the “basic” or “fundamental” or “irreducible” qualities are set in motion — something that IDers stipulate could not have happened through “blind” and “dumb” processes — then tinkering of the microevolutionary sort is permissible. In other words, an intelligent designer is necessary to design the eye, but once designed, the eye could microevolve into diverse versions.

A more likely answer, however, is that ID creationists do not deny microevolution because they cannot deny it. It is perfectly obvious and incontrovertible that it happens. We see variations in traits, even wholly new traits, emerge in existing species routinely and ordinarily. Bacteria and viruses (micro-) evolve new drug-resistant strains. Insects (micro-) evolve into new types. We humans have even artificially (micro-) evolved dogs and cats, for instance, into a plethora of different breeds, and with genetic technologies we stand on the verge — or have crossed the verge — of (micro-) evolving all kinds of plants and animals. It would require a suicidal degree of stupidity to deny that microevolution happens rather often and easily. Scientific creationists insist, however, that such events have nothing to do with and lend no credence to macroevolution.

Is Microcreation An Effective Argument?

It is plain to see that ID theory and research is a kind of microcreationist project, on a par with microevolution. Both are interesting programs, but neither addresses the bigger and ultimately unavoidable questions. Still, no doubt microcreation is meant to pave the way for macrocreation, in the same manner that microevolution is an incremental step in macroevolution. The two questions for us are, then: (1) Does microcreation make the case for macrocreation stronger, and (2) Does microcreation make the case for macroevolution weaker? Unfortunately for the ID enthusiasts, both answers are no. It is, in the end, an ineffective argument, even if it were to prove true.

Why does microcreation not strengthen the case for macrocreation? First and foremost, macrocreation is at best an analogy or extrapolation of microcreation and at worst an erroneous misapplication of it — an instance of the fallacy of composition. This well-known fallacy states that you should not ascribe a characteristic to a whole object simply because it is ascribed to part of the object. The same might be contended about microevolution, but it really cannot be, as we will see below.

One of the many serious charges against microcreation is that it does not offer any specific mechanisms for the creation process. If a flagellum or an eye or a clotting system is designed, how is it designed? A claim is not scientific or theoretical merely by taking factual topics as its subject; a scientific or theoretical answer must suggest some mechanisms or means by which those facts came about. Just saying, “It is designed” says nothing. What are the steps in the design process? How is that design implemented into real physical matter? If such questions cannot be answered at the microcreation level, then it is useless as a premise for the macrocreation level.

Related to the question of design method is the question of designer: who or what is this designer? ID theorists cannot evade the fact that a specific intelligent entity is being posited as the solution to what they consider otherwise insurmountable problems; “mindless” natural processes cannot account for the results, so there must be a mindful processor. But again, this is a nonanswer without more content. Admittedly, Behe speculates about a creator, supposing that it might be an alien life form or an interdimensional being, or even the conventional idea of a god. However, speculation is not knowledge, and the answer — whatever answer — ID settles upon, it faces another even more vexing question: where did that designer come from? If all irreducibly complex phenomena have a creator, and the creator is him/itself irreducibly complex, then he/it must have a creator, ad infinitum. Having not solved this problem (in fact, having probably started an insoluble problem), they cannot extrapolate a solution from micro to macro.

Finally, while microcreation might solve one microproblem — that is, the explanation of “function” or “purpose” at the micro level — it says nothing and can say nothing about the issue of macrofunction or macropurpose. Okay, let us grant that the purpose of all the irreducibly complex parts of a flagellum is the motility of a protist, and some intelligence has created and assembled the parts for that function. What is the purpose of the protist? A single-celled life form is indisputably complex, but what is it for? Design without purpose is irrational; designed has to mean not only “designed by” but “designed for.” Let us grant that the human eye is designed for the purpose of vision in a human being. What is the purpose of vision? What is the purpose of the human being? Similarly, what is the purpose of a mosquito, a planet, or a universe? At the macro level, purpose seems to escape, even if it is detectable at the micro level. I suppose it might be possible to conclude that an intelligence designed the flagellum and then left it for protists to exploit, or that he/it designed the eye and then left it for humans to exploit, but I am sure that this is not where macrocreationists want to end up, and it also seems ultimately absurd. You cannot leave flagella and eyes lying about and expect anything interesting to happen to them.

So it seems that even if we grant the microcreationists their claims (and we do not), this does not aid macrocreationist claims one bit. Let us then consider our other question: does microcreation decrease the likelihood or sensibleness of macroevolution? Again, the answer is no. First, microcreation does not refute microevolution and may in fact depend on it; perhaps a designer designed the first flagellum or eye, but unless he, she or it was very industrious, each particular instantiation of a flagellum or eye was not independently created. That is, even if we grant that “the eye” (the basic blueprint or plan for an eye) was designed, that does not mean — and I don’t think that microcreationists want to insist — that the human eye was designed independently of the cat eye independently of the fish eye independently of the bird eye, etc. So they could allow and probably must allow that, having set the “model” or “blueprint” in motion, the designer could or did step back and let microevolutionary processes run.

Also, as we said, creationists cannot deny microevolution, unless they want to maintain that every time a new strain of virus evolves it is really the designer stepping back in to redesign his creation. While possible to imagine, it is hard to believe and impossible to prove, and it still raises the objection: why would a beneficent designer keep improving his pests?

The really damaging aspect of the creationist tolerance of microevolution, though, is this: microevolution has a mechanism. Even the most hardheaded creationist who accepts the reality of microevolution must admit that it operates by natural processes such as natural selection, genetic drift, mutation, symbiosis, preferential selection, and the like. However, having allowed these processes into the world, there is no way to restrict their scope. If these processes can effect minor, or at least intraspecies modification over remarkably short time spans, there is no reason in principle why these same processes could not effect major modification, i.e., speciation, over remarkably long time spans.

Further, since microevolution does not depend on a problematic concept like (micro) purpose, there is no demand that macroevolution satisfy any (macro-) purpose qualifications. Evolution, from Darwin on, relies strictly on “blind” or non-teleological forces, and ones which work equally well at the micro and macro levels. That is why we stated at the outset that evolution is a complete theory: it encompasses both micro and macro variation and emergence under exactly the same mechanisms. It does not need (although it might with effort be made consonant with) any ancillary or external forces or factors. In other words, microevolution is the same thing as macroevolution in every important sense, and microcreation does not and cannot change that fact. In reality, it is a much larger leap from microcreation to macrocreation than it is from microevolution to macroevolution.

One last objection that some anti-evolutionists might raise is that the “transitional forms” that we predict do not exist. They contend this weakens, if not falsifies, the case for evolution. The response to this charge is three-fold. First, a great number of transitional forms have been discovered, and it is disingenuous of critics to keep demanding “missing links” when links are provided; it is always possible to say, “OK, you found a link between 1 and 2, namely 11/2, but what is the missing link between 1 and 11/2 ?” This reductio ad absurdum must be resisted, and creationists must be compelled to explain when they would be satisfied with the intermediate evidence. My fear is that they never will be.

Second, critics of evolution must concede that evolutionary research has not been going on all that long, and that the limitations of fossilization and excavation make discovery of any forms, transitional or not, a tricky affair. Some evolutionists have even suggested that the periods of transition may have been relatively short and abrupt (the notion of “punctuated equilibrium”), a sudden mass speciation something akin to the sudden mass extinctions at the end of the Permian and the Cretaceous periods. If this is the case, then transitional forms would be the least likely to be unearthed today. Some respond that this is an opportunistic solution to a serious problem, and it may be, or it may be an accurate solution to the problem.

Third and finally, the demand for transitional forms is a double-edged sword for creationists. Adversaries of creationism might with justification ask for evidence of transitional designs. This evidence might consist of either designs that are in between other designs (i.e., the transitional eye between a human and cat or a human and reptile) or that are “under development” or unfinished (i.e., the blueprint for an eye or an eye “in progress”). Since I have never heard of any such evidence, nor have I heard a microcreationist speak of such evidence, I conclude that it does not exist. Of course, they might respond that the designer is not only intelligent but perfect, so he, she or it does not make in-between or unfinished designs, but this is an additional postulated quality of the designer that itself must be proved, and the claim is at least as opportunistic as any punctuated equilibrium theory that evolutionists have ever advanced.

Conclusion: The Failure of Microcreation

Microcreation fails in every regard. It is not a complete explanation of natural phenomena. It fails on a number of levels: it does not account for macrolevel entities, nor does to lead inevitably to macrocreation as a “second stage” in creation, nor does it posit a mechanism by which either could occur. Additionally, it does not refute evolution as a sound and complete explanation of the same phenomena. In fact, it generally grants microevolution, which does inevitably lead to macroevolution as a second stage in evolution and does provide a mechanism by which both occur.

For, in the end, microevolution is nothing more than descent with modification over the short term, and macroevolution is descent with modification over the long term. Put another way, macroevolution is merely the accumulation of microevolutionary changes. The only difference between them is time-scale. The same thing cannot be said about microcreation and macrocreation. Macrocreation is not the accumulation of microcreationist events; if it were, then macrocreation would be “blind” or incidental. You do not get a flagellum over the short term and a protist over the long term. Where would the flagellum reside in the meantime? We can conclude with confidence that microcreation fails as an explanation even of microlevel phenomena and that, even if it were it to succeed at that level, it would still fail as a ground for macrocreation.

References

1. Behe, Michael. 1996. Darwin’s Black Box. NY: The Free Press.
2. For instance, Barrow, John and Tipler, Frank 1988. The Anthropic Cosmological Principle. NY: Oxford University Press and Tipler, Frank 1995. The Physics of Immortality: Modern Cosmology, God, and the Resurrection of the Dead. NY: Doubleday.

Hamlet Revisited:
How Evolution Really Works

by William Standsfield

MICHAEL SHERMER’S ARTICLE “To Be or Not to Be a Weasel: Hamlet, Intelligent Design, and How Evolution Works” (Skeptic magazine Vol. 9, No. 4, 16–20) discussed the metaphor originally produced (independently) by Richard Hardison and Richard Dawkins, in which imaginary monkeys pound on a typewriter to produce a line from Shakespeare’s Hamlet. Using Hardison’s example, “To Be Or Not To Be,” he tacitly assumes that every letter of the alphabet has an equal opportunity of being typed each time the monkey hits a key. If we ignore the five spaces in the phrase and discount capital versus lower case letters, the probability that the 13-letter sequence “tobeornottobe” could be typed by chance is the inverse of “26 to the 13th power.” However, it is possible to use a computer program to “randomize alphabet selection until a T is drawn. Then it will be programmed to do the same for the O and continue accordingly for all desired 13 letters.” In theory, using this procedure, the phrase is expected to be typed in 1 out of 338 trials. Hardison claims this procedure (which Richard Dawkins calls “ratcheted cumulative selection”) is more akin to how natural selection works than the previous nonselective method where none of the individual letters have any adaptive value of their own apart from the complete 13 letter sequence.

Shermer’s article includes several critiques of Hardison’s method by other correspondents. R. Reece suggests that perhaps “Two be or knot too be” is “close enough for evolutionary forces to generate.” Reece thus allows 3 letters to be added to the sequence without destroying its sense when verbalized.

Bill Kittler would “allow ‘nonsense’ sequences between the correspondence elements (e.g., ‘cAStYOUsLIKE’ or even ‘AcSYOgULIzKE)’” as a developmental stage for producing the title of Shakespeare’s play AS YOU LIKE IT. All that is needed for perfection is a process for removing nonsense sequences.

All of these artificial programs are merely metaphors for the processes of organic evolution, i.e., generation of heritable variations by random mutations, recombination of homologous DNA sequences during the formation of gametes (meiosis), and preservation of the more favorable variants by differential reproductive success via natural selection.

I can’t resist the temptation to try to put these metaphors into a more biological context. Each gene consists of a unique sequence of four nucleotides (A, T, G, and C) in a DNA molecule. Gene expression involves the transcription of the gene sequence into a kind of “mirror image” molecule called messenger RNA (mRNA). Ribosomes translate the mRNA sequence into a string of amino acids that comprise a protein molecule. The traits that a multicellular organism possesses are functions of the kind, amount, locations, and timing of the proteins made by its various cells. An average size protein chain contains about 300 amino acids in a specific sequence, like the letters of our phrase “tobeornottobe.” Some proteins consist of a single chain of amino acids; other proteins must contain two or more identical chains to be functional; still others may consist of two or more dissimilar chains (each kind of chain specified by it own gene).

There are 20 kinds of amino acids from which biological proteins are naturally made. Each amino acid is encoded by a triplet of 3 adjacent nucleotides (a codon) in DNA (and its mirror image in mRNA). There are 4 x 4 x 4 = 64 possible codon permutations. Three of these triplets are referred to as “nonsense codons.” They do not code for any amino acid. Instead they serve as signals to terminate translation of the protein chain; Kittler’s use of the term “nonsense sequences” is unfortunately inappropriate here. All of the remaining 61 possible triplets specify an amino acid and are called “sense codons.” Some amino acids have only one corresponding codon; others may have 2, 3, 4, or 6 synonymous triplets that are called “samesense” codons. Thus, there is a lot of redundancy in the genetic code and selection cannot discriminate between same sense mutations. For example, consider a short segment of a protein chain containing 5 amino acids. One amino acid is represented in the genetic code by only one codon, another has 2 samesense codons, another with three, another with four, and another with six. The number of different DNA molecules that could code for this string of 5 amino acids is 1 x 2 x 3 x 4 x 6 = 144. “Missense codons” specify amino acids that are different than those of the original DNA in which they occurred. Proteins bearing altered amino acid sequences may be harmful or beneficial (both in various degrees) or selectively neutral depending on several factors.

Most protein chains spontaneously fold back and forth on themselves into intricate patterns produced by various kinds of bonds between nonadjacent amino acids that tend to produce the energetically most stable molecules. The natural configuration of each kind of protein in a defined environment is thus unique. Each protein enzyme contains a set of amino acids in a specific configuration (called its reactive site) that can associate closely with its substrate like a “lock and key” or a “hand and glove.” The same is true for the interaction of a protein antibody and its cognate antigen or, in general, the way that any protein chains associate with one another. The recognition or reactive site may contain amino acids that are not closely linked on the same chain (or perhaps even on other chains) because of the characteristic way that a functional protein folds up into its most stable configuration. Any mutation that can increase the stability of a protein (e.g., to a wider range of temperatures, hydrogen ion concentrations, or other environmental variables), enhance its biological activity, reaction specificity, and circulation half-life, or control the expression level in an adaptive way would tend to be perpetuated in a population by natural selection.

Since there are 26 letters in the alphabet and only 20 amino acids, let’s delete the last six letters of the alphabet (uvwxyz). This will leave 20 letters, each of which can be assigned to one of the amino acids. Let us envision a segment of an ancestral protein that contains none of the 13 amino acids in our phrase “tobeornottobe.” The original protein was obviously adaptive, or else organisms could not have survived and reproduced. We can imagine that over millions of years of evolution the 13 original amino acid sites have gradually been replaced by those in our phrase. Let the order of these sites be numbered 1 to 13, left to right in the protein chain.

It is highly unlikely that the order with which each of these sites was replaced would be exactly the same as their linear order in the chain (as suggested by Hardison’s model). For example, the 7th letter (n) in the phrase might have been the oldest replacement, whereas the most recent replacement could be the 3rd letter (b). It is also highly unlikely that all seven replacements in a chain of about 300 amino acids would be grouped together in one contiguous segment. It is much more likely that the 13 sites where replacements have occurred would be nonadjacent and separated by perhaps as many as 11 segments containing the original amino acids of the ancestral sequence (as suggested by Kittler). If each of the amino acid replacements made the organism in which it occurred more adaptive to the local environment in which it lived, then organisms possessing each stage of mutated protein (produced by ratcheted cumulative selection) survived and reproduced more offspring than those with the immediate ancestral sequence. However, there may be one or more “nonessential” segments of a protein chain outside of its reactive/ recognition site(s) that could be modified by certain kinds of DNA missense mutations and yet have no effect on the functioning of that protein. Such a “selectively neutral” mutation would be unlikely to be retained in a population unless it was closely linked (hitchhiking) on the same DNA molecule to an otherwise well adapted nucleotide sequence.

In either event, over many generations, the frequency of the ancestral amino acids at each of the 13 sites would gradually diminish as the frequency of the more adaptive amino acid substitutions (or selectively neutral hitchhickers) increased in the population. It is unrealistic to think that any one of these adaptive replacements at any one site must spread throughout the population (gradually reducing the incidence of the ancestral amino acid at that site to a rare occurrence) before natural selection could begin the process of replacing one or more other amino acid sites. At any given time in the evolution of a protein, there may have been two or more sites in the process of being replaced by more adaptive amino acids. In the human population, for example, there currently are more than 100 amino acid substitutions known in the beta chains of normal adult human hemoglobin. Most of these variants produce a functional protein, so most people who carry them are usually unaware of it. By contrast, the full meaning (function) of the English phrase “tobeornottobe” makes no sense (is not fully functional) until all 13 letters are in their respective positions.

At the level of the gene, it may be more difficult to make the typing metaphor understandable in biological terms than it is at the level of the protein. This is partly because a string of 13 x 3 = 39 nucleotides is minimally required to code for a string of 13 amino acids. The number of mutations occurring in a gene cannot be accurately estimated from the number of amino acid substitutions in the protein product of the gene. The reason for this is that many mutations may be “samesense” and produce no change in the amino acid sequence of the protein. In addition, many genes in the nucleated cells of plants and animals have one or more coding regions (exons) interrupted by noncoding regions (introns). These “split genes” are transcribed in the normal way into mRNA molecules within the cell’s nucleus. However, the mRNAs must have their introns removed and their exons spliced together before they are released into the cytoplasm to be translated into protein chains by ribosomes. If Kittler’s “nonsense” sequences are considered to be noncoding introns, there does exist a mechanism for removing them during the nuclear processing of mRNA molecules. As long as mutations within introns do not interfere with the excision and splicing processes, we would not expect them to be subject to selection that operates at the level of the trait determined by the protein. (Introns and DNA segments between genes do not code for proteins, and used to be called “junk DNA.” Recently however, some of this “junk” has been found to be transcribed into small RNA molecules that can have a profound influence on the behavior of cells by interacting with other RNA molecules, with DNA, with proteins, or with small chemical molecules. Our failure to recognize the significance of these microRNAs “may well go down as one of the biggest mistakes in the history of molecular biology.”)

Reece’s sequence “twobeorknottoobe” introduced 3 additional letters to the standard 13-letter phrase. Messenger RNA molecules are translated by ribosomes reading three adjacent nucleotides at a time coding for each amino acid. Introducing one additional nucleotide to a gene results in mRNA molecules that have shifted their “reading frame” by one nucleotide from the point of the addition on through the remainder of the molecule. Ordinarily a frame shift mutation (single nucleotide addition or deletion) would create many “missense” mutations that specify the wrong amino acids in the protein chain. They could render the protein useless if they occurred in the reactive site of the chain or caused the chain to fold improperly. If the shifted reading frame created a nonsense triplet, the length of the protein would prematurely stop there and the truncated protein would probably not function. In a few cases it has been possible to show that two or more frameshift mutations coding for a “nonessential region” of a protein may restore the correct reading frame. For example, one nucleotide addition and one nucleotide deletion compensate for one another to restore the correct reading frame; only the codon sequence between the two mutations would be in the wrong reading frame. Three additions (or three deletions) would also restore the reading frame. The region between the first and third mutations would be in the wrong reading frame; for 3 additions, the protein chain would be one amino acid longer than normal; for 3 deletions, the protein chain would be one amino acid shorter than normal.

New genes can be created by bringing together, as exons of a single gene, several coding sequences that had previously specified different proteins or different structural or functional domains of the same protein, through intron-mediated recombination. This process is called exon shuffling. Each different letter of our phrase could represent a different exon in a gene assembled by exon shuffling.

Occasionally an entire gene or even longer DNA nucleotide sequence may become duplicated. The duplicate gene may then experience one or more mutations of various kinds that may allow its protein product to perform new adaptive functions. These mutational changes can evolve without diminishing the organism’s fitness because the original gene continues to carry out its normal function while the duplicate gene goes its own evolutionary way. For example, it is thought that the photosensitive protein opsin, sensitive to red light in birds and primates, differs because the primate version arose anew in Old World primates from a duplication of the green opsin gene. Over time, the duplicated gene accumulated mutations that made it encode a protein sensitive to red wavelengths.

Metaphors can sometimes be very useful educational tools. However, I believe that the typing-monkeys metaphor generated by Hardison and Dawkins are so unlike biological realities and the way that natural selection operates that they will only tend to confuse students, rather than help them learn. My advise to teachers is “quit monkeying around.” Just tell it like it is.

Flashbulb Memories

by Daniel Greenburg

On arrival in New York we caught a cab and headed for the city. The cab had no radio on. As fate would have it, the cabby missed a turn somewhere and we were off the highway, somewhere in Astoria, Queens, I think. We were stopped for a red light when a woman came out of her house screaming and crying. I rolled down the cab window to ask what the matter was… She told me that John Kennedy had just been shot in Dallas. We drove the rest of the way in silence.

— Richard Nixon’s memory of the Kennedy assassination¹

Although I was but four and a half years old when [the President] died, I distinctly remember the day when I found on our two white gate posts American flags companioned with black. I tumbled down on the harsh gravel walk in my eager rush into the house to inquire what they were “there for.” To my amazement I found my father in tears, something that I had never seen before, having assumed, as all children do, that grown-up people never cried. The two flags, my father’s tears, and his impressive statement that the greatest man in the world had died constituted my initiation…[into] a world lying quite outside the two white gate posts.

— Jane Addams’s memory of the Lincoln assassination²

MOST OF US CAN TELL STORIES LIKE THESE. Shocking events seem to etch themselves in our minds; we recall them with a clarity and emotional intensity that few other memories can match. We remember more than just the basic facts of the event; we know our personal stories as well — where we were, who told us, and what we were doing when we heard the news. Even trivial details seem to fix themselves in our memories: on the day of the Kennedy assassination, for example, Julia Child remembers that she and her husband were eating fish soup. Some people notice strange and compelling coincidences: Arthur Sulzberger was discussing presidential security when Kennedy’s death was announced; Billy Graham had a sense of foreboding a week before; Bob Hope had just received a signed photograph of himself with Kennedy, which was sitting atop the television on which he heard the news. All of these features are unusual and intriguing, but the long life of these memories stands out above all else. Few of us can remember what we did on the day before a shocking event; as for the day itself, we feel that we can see it in our minds, that we can remember it as though it were yesterday, and we feel that that we cannot possibly forget it.

The vividness and apparent durability of these memories has fascinated psychologists for over a century. In 1899, a psychologist named F. W. Colegrove investigated people’s 34-year old memories of the Lincoln assassination. He found that over two-thirds of the people he interviewed could remember what they had been doing when they heard the news, a result he considered a testament to “the abiding character of vivid experiences.”³ Decades later, when Roger Brown and James Kulik of Harvard University studed memories of shocking events of the 1960s and 1970s they proposed the term “flashbulb memory” to capture what they described as “the primary, ‘live’ quality [of the memories] that is … very like a photograph.” ⁴ As Brown and Kulik noted, the metaphor is not perfect, as some details are not preserved, but on the whole it aptly describes the strength and clarity of the memories as well as the rapidity with which they are originally stored.

We may have flashbulb memories for private events as well, such as a first kiss or the birth of a child, but the most compelling flashbulbs — the ones that we find ourselves relating over and over — tend to involve shocking historic events. Thus, people have reported flashbulb memories for many occasions, including the Lincoln assassination, the attack on Pearl Harbor, the assassinations of John F. Kennedy and Martin Luther King, the attempted assassination of President Reagan, the 1989 San Francisco earthquake, the Challenger explosion — and, most recently, the September 11th attacks.⁵

The Strange Case of the President’s Memory

Shortly after 9/11, one particular person’s memories attracted the attention of the Internet’s conspiracy theorists. That person was President George W. Bush, and the controversy arose over apparent changes in his story. The fuss began on December 4, 2001, when the President told a crowd of people how he heard the news about the attacks:

I was in Florida. And my chief of staff, Andy Card — actually I was in a classroom talking about a reading program that works. And I was sitting outside the classroom waiting to go in, and I saw an airplane hit the tower — the TV was obviously on, and I use[d] to fly myself, and I said, “There’s one terrible pilot.” And I said, “It must have been a horrible accident.” But I was whisked off there — I didn’t have much time to think about it, and I was sitting in the classroom, and Andy Card, my chief who was sitting over here walked in and said, “A second plane has hit the tower. America’s under attack.”⁶

Just over two weeks later, on December 20, the President told a different story during an interview with the Washington Post:

Bush remembers senior adviser Karl Rove bringing him the news, saying it appeared to be an accident involving a small, twin-engine plane. In fact it was American Airlines Flight 11, a Boeing 767 out of Boston’s Logan International Airport. Based on what he was told, Bush assumed it was an accident. “This is pilot error,” the president recalled saying. “It’s unbelievable that somebody would do this.” Conferring with Andrew H. Card Jr., his White House chief of staff, Bush said, “The guy must have had a heart attack”… At 9:05 a.m., United Airlines Flight 175, also a Boeing 767, smashed into the South Tower of the trade center. Bush was seated on a stool in the classroom when Card whispered the news: “A second plane hit the second tower. America is under attack.”⁷

Then on January 5, 2002, the President’s story changed again:

I was sitting there, and my Chief of Staff — well, first of all, when we walked into the classroom, I had seen this plane fly into the first building. There was a TV set on. And you know, I thought it was pilot error and I was amazed that anybody could make such a terrible mistake. And something was wrong with the plane, or — anyway, I’m sitting there, listening to the briefing, and Andy Card came and said, “America is under attack.”⁸

Clearly, something is wrong here. In the second memory, the President claims that Karl Rove told him about the first crash, but in the first and third memories, he claims that he saw the news on television. Stranger still, the first and third memories seem impossible: there was no footage of the first plane, at least not at that hour of the morning.⁹ What could the explanation be? Conspiracy theorists had plenty of suggestions. Sites across the Web erupted with accusations of dishonesty and calls for impeachment. “Bush slip reveals total 9/11 complicity,” screamed freeworldalliance.com:

Complicit factions of the U.S. federal government, including virtually ALL upper-level members of the BushMob, actually FILMED their own attack on New York’s World Trade Center — and Bush has admitted that he WATCHED IT!!!! And there is only one POSSIBLE way such footage COULD have existed: the perpetrators of the WTC attack HAD THEIR OWN CAMERAS IN PLACE TO FILM IT [emphasis in the original].¹⁰

The website bushwatch.com took a somewhat more moderate view, noting that “the most benign conclusion, then, is that Bush was not telling the truth when he told Jordan that he saw the first plane hit the first tower prior to his going into the classroom.”¹¹ Even the Guardian, a British newspaper, found Bush’s statements worthy of comment, noting that “the story that he was watching TV contradicts reports from correspondents at the time that he got the news in a phone call.”¹²

What are we to make of this? Are we obliged to believe that the President is smart enough to carry out a horrific conspiracy to attack America, but dumb enough to reveal it — twice? Should we instead believe that the President lied about what happened — twice but not three times — even though he had much to lose and nothing to gain from such a lie? Or should we believe something else entirely?

Fortunately, scientific studies of memory can offer a more benign explanation. We don’t need to posit irrational lies or a massive conspiracy imperfectly hidden from the eyes of everyday citizens. Instead, we need only consider the frailties of human memory.

The False Memory Phenomenon

All of us know that our memory can fail us — we forget the location of our car keys, the name of our second-grade teacher, or the kind of drink we had with lunch three days ago. But memory can betray us in another way, too: we may also experience false memories — putative “memories” for events that never took place. While forgetting is easy to notice, false memories are much harder to detect because they can seem just like normal memories. Nevertheless, over the last century, hundreds of studies have shown just how common false memories can be.

Consider one of the most straightforward demonstrations of false memory — originally proposed by James Deese — which has been used in introductory psychology classrooms as well as experimental research. An experimenter reads a list of about a dozen words (“bed, rest, awake, tired, dream,” etc.), all of which are related to one particular word, known as the lure (in this case, “sleep”). The listeners are then asked to recall as many words as they can. In one sense, people perform quite well — they can remember most of the words on the list. Yet in one particular way, they perform quite poorly: many people falsely recall hearing the lure, even though the experimenter never read it. This is not just a vague impression or a guess; people will often express great confidence in their memory of the lure, saying that they can “hear” the experimenter’s voice in their minds, or that they remember exactly when in the list it was presented. (In fact, their confidence can be so strong as to be unshakable. When I first watched an instructor try this on her class, a few students simply refused to believe that she never read the lure, instead asserting that she must be lying!)

In another classic experiment, Elizabeth Loftus and John Palmer showed people a videotape of a car accident. They then asked participants a series of questions about what they had seen. One of the questions had two forms: half of the participants estimated how fast the cars had been going when they hit each other; the other half estimated how fast the cars were going when they smashed. This simple one-word difference produced a startling effect: while most people got the question right, participants who received the “smashed” question were more likely to claim that they had seen broken glass, even though there was no broken glass in the original video. In short, our memory of an event can be altered by the way in which someone asks us about it — a problem that proves particularly vexing to police officers and lawyers.

In some cases, people can even have entirely fictitious memories for full-fledged, specific events. In one study, Ira Hyman and Joel Pentland of Western Washington University tried to “implant” a false memory in the minds of their participants. They started