Darwin's Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design

by Stephen C. Meyer

domestic animals—

sheep,

animals

certain traits

to b...

sheep...

in a cold northern climate (or to harve...

woolliest sheep

key is man’s power of accumulative selection,”

“Nature gives successive variations; man adds them up in certain directions useful to him.”3

“short-faced tumbler,”

pouter, with its elongated legs, wings, and body overshadowed by its “enormously developed crop, which

will the result not be the same as before?

intelligent agent.

Nature

specifically, those that conferred a functional or survival advantage upon the organisms possessing them—causing the fea...

not by “artificial selection”—but by a wholly natural process.

On the Origin of Species

his skill in dispensing with potential objections unrivalled.

geologic history, a period that at first was commonly called the Silurian, but later came to be known as the Cambrian.

During this geological period, many new and anatomically sophisticated creatures appeared suddenly in the sedimentary layers of the geologic column without any evidence of simpler ancestral forms in the earlier layers below, in an event that paleontologists today call the Cambrian explosion.

“The difficulty of understanding the absence of vast piles of fossiliferous strata, which on my theory were no doubt somewhere accumulated before the Silur...

Agassiz concluded that the fossil record, particularly the record of the explosion of Cambrian animal life, posed an insuperable difficulty for Darwin’s theory.

brachiopods

brachiopod

As shown in the accompanying figure, it possesses a gonad, mantle, mantle cavity, anterior body wall, body cavity, gut, and lophophore, the last of which is a feeding organ like a ring of tentacles, usually in the shape of a coil or horseshoe, with a mouth inside the ring of tentacles, and an anus outside. The brachiopod exhibits a highly complex overall body plan, with many individually complex and functionally integrated anatomical systems and parts. Its tentacles, for instance, are covered by cilia precisely arranged to generate and direct a current of water toward the mouth.6

pairs for the head. Most dramatic of all were the compound eyes found on even some of the very early trilobites—eyes that afforded these not so primitive animals a 360-degree field of vision.7

(2) the heritability of those variations, and

a

Darwin, variations in traits arise randomly.

Darwin conceded that the beneficial variations responsible for permanent change in species are both rare and necessarily modest. Major variations in forms, what later evolutionary biologists would term “macromutations,” inevitably produce deformity and death. Only minor variations meet the test of viability and heritability.

It followed that, over human timescales, the benefits of this evolutionary mechanism would be difficult or impossible to spot. But given enough time, favorable variations would gradually accumulate and give rise to new species and, given more time, even fundamentally new groups of organisms and body designs.

If artificial selection could conjure so many strange breeds from a wild strain in a few centuries, Darwin argued, imagine what natural selection could achieve over many millions of years. Even the origin of complex structures such as the mammalian eye—which seemed at first to present a significant challenge to his theory—could be explained if one postulated the existence of an initially simple...

Darwin’s mechanism of natural selection and random variation necessarily required a lot of time to generate wholly novel organisms, creating a ...

In an 1874 Atlantic Monthly essay titled “Evolution and the Permanence of Type,” Agassiz explained his reasons for doubting the creative power of natural selection. Small-scale variations, he argued, had never produced a “specific difference” (i.e., a...

To produce truly novel animal forms, the Darwinian mechanism would—by its own internal logic—require not only millions of years, but untold generations of ancestors. Thus, even the discovery of a handful of plausible intermediates allegedly linking a Precambrian ancestor to a Cambrian descendant wouldn’t come close to fully documenting Darwin’s picture of the history of life.

If Darwin is right, Agassiz argued, then we should find not just one or a few missing links, but innumerable links shading almost imperceptibly from alleged ancestors to presumed descendants. Geologists, however, had found no such myriad of transitional forms leading to the Cambrian fauna. Instead, the stratigraphic column seemed to document the abrupt appearance of the earliest animals.

Agassiz thought the evidence of abrupt appearance, and the absence of ancestral forms in the Precambri...

MURCHISON, SEDGWICK, AND THE CAMBRIAN FOSSILS OF WALES Darwin, for his part, responded with more than civility. Far from dismissing Agassiz, he conceded that his objection carried considerable force. Nor was Agassiz alone in pressing these concerns. Other leading naturalists thought the fossil evidence presented a significant obstacle to Darwin’s theory.

“You have deserted—after a start in that tram-road of all solid physical truth—the true method of induction.”14

Then, in the Triassic period that follows, completely novel animals such as turtles and

DATING BY DISCONTINUITY Already by Sedgwick’s time, the various strata of fossils had proved so distinct one from another that geologists had come to use the sharp discontinuities between them as a key means for dating rocks. Originally, the best tool for determining the relative age of various strata was based on the notion of superposition. Put simply, unless there is a reason to believe otherwise, a geologist provisionally assumes that lower rocks were put down before the rocks above them. Now, contrary to a widespread caricature, no respected geologist, then or now, adopts this method uncritically. The most basic training in geology teaches that rock formations can be twisted, upended, even mixed pell-mell by a variety of phenomena. This is why geologists have always looked for other means to estimate the relative age of different strata.

1815, Englishman William Smith had hit upon just such an alternative means.19

Even when layers of geological strata are twisted and turned, the clear discontinuities between the various strata often allow geologists to discern the order in which they were deposited, particularly when there is a broad enough sampling of rich geological sites from the period under investigation to study and cross-reference.

Agassiz, for his part, would have none of it. “Both with Darwin and his followers, a great part of the argument is purely negative,” he wrote. They “thus throw off the responsibility of proof. . . . However broken the geological record may be, there is a complete sequence in many parts of it, from which the character of the succession may be ascertained.” On what basis did he make this claim? “Since the most exquisitely delicate structures, as well as embryonic phases of growth of the most perishable nature, have been preserved from very early deposits, we have no right to infer the disappearance of types because their absence disproves some favorite [i.e., Darwinian] theory.”25

Though Darwin himself was less than enthusiastic about his response to Agassiz’s objection, it seemed adequate to satisfy the needs of the moment.

True, some scientists, notably the Scottish engineering professor Fleeming Jenkin and (later) the English geneticist William Bateson, expressed persistent doubts about the efficacy of natural selection. But despite the views of some weighty scientific critics, Darwin’s revolutionary theory won increasingly wide support and soon defined the terms of the debate about the history of life. Those who rejected it wholesale, as Agassiz did, consigned themselves to increasing irrelevance.

mystery, at least, waiting to be solved?

Pied Piper.”

many historians