Stephen Jay Gould

All life on earth - everything from bacteria to mushrooms to hippos - shares an astonishing range of detailed biochemical similarities, including the structure of heredity in DNA and RNA, and the universal use of ATP as an energy-storing compound. Two possible scenarios, with markedly different implications for the nature of life, might explain these regularities: either all earthly life shares these features because no other chemistry can work, or these similarities only record the common descent of all organisms on earth from a single origin that happened to feature this chemistry as one possibility among many.

But all evolutionary biologists know that variation itself is nature's only irreducible essence. Variation is the hard reality, not a set of imperfect measures for a central tendency. Means and medians are the abstractions.

If we choose a weak and foolish speculation as a primary textbook illustration (falsely assuming that the tale possesses a weight of history and a sanction of evidence), then we are in for trouble - as critics properly nail the particular weakness, and then assume that the whole theory must be in danger if supporters choose such a fatuous case as a primary illustration.

[G]enes make enzymes, and enzymes control the rates of chemical processes. Genes do not make “novelty seeking” or any other complex and overt behavior. Predisposition via a long chain of complex chemical reactions, mediated through a more complex series of life's circumstances, does not equal identification or even causation.

The solution, as all thoughtful people recognize, must lie in properly melding the themes of inborn predisposition and shaping through life's experiences. This fruitful joining cannot take the false form of percentages adding to 100—as in “intelligence is 80 percent nature and 20 percent nurture,” or “homosexuality is 50 percent inborn and 50 percent learned,” and a hundred other harmful statements in this foolish format. When two ends of such a spectrum are commingled, the result is not a separable amalgam (like shuffling two decks of cards with different backs), but an entirely new and higher entity that cannot be decomposed (just as adults cannot be separated into maternal and paternal contributions to their totality).

Theories rarely arise as patient inferences forced by accumulated facts. Theories are mental constructs potentiated by complex external prods (including, in idealized cases, a commanding push from empirical reality). But the prods often include dreams, quirks, and errors—just as we may obtain crucial bursts of energy from foodstuffs or pharmaceuticals of no objective or enduring value. Great truth can emerge from small error. Evolution is thrilling, liberating, and correct. And Macrauchenia is a litoptern.

I believe […] that we can still have a genre of scientific books suitable for and accessible alike to professionals and interested laypeople. The concepts of science, in all their richness and ambiguity, can be presented without any compromise, without any simplification counting as distortion, in language accessible to all intelligent people. […] I hope that this book can be read with profit both in seminars for graduate students and—if the movie stinks and you forgot your sleeping pills—on the businessman's special to Tokyo.

Yes, Shakespeare foremost and forever (Darwin too). But also teach about the excellence of pygmy bushcraft and Fuegian survival in the world's harshest climate. Dignity and inspiration come in many guises. Would anyone choose the tinhorn patriotism of George Armstrong Custer over the eloquence of Chief Joseph in defeat?

Mythology is wondrous, a balm for the soul. But its problems cannot be ignored. At worst, it buys inspiration at the price of physical impossibility […]. At best, it purveys the same myopic view of history that made this most fascinating subject so boring and misleading in grade school as a sequential take of monarchs and battles.

When scientists need to explain difficult points of theory, illustration by hypothetical example - rather than by total abstraction - works well (perhaps indispensably) as a rhetorical device. Such cases do not function as speculations in the pejorative sense - as silly stories that provide insight into complex mechanisms - but rather as idealized illustrations to exemplify a difficult point of theory. (Other fields, like philosophy and the law, use such conjectural cases as a standard device.)

Darwin himself told us in his last book (The Formation of Vegetable Mould Through the Action of Worms) that we should never underestimate the power of worms on the move. ...The inversion of a humble worm, especially when disturbed, may bring down empires. Shakespeare told us that "the smallest worm will turn being trodden on." And Cervantes wrote in his author's preface to Don Quixote that "even a worm when trod upon, will turn again." ...Geoffrey, it seems, was correct after all - not in every detail, of course, but at least in basic vision and theoretical meaning. And the triumph of surprise, the inversion of nuttiness to apparent truth, stands as a premier example of the most exciting general development in evolutionary theory during our times.

In his anti-Darwinian book... (and eponymously named The Neck of the Giraffe), Francis Hitching tells the story... "The need to survive by reaching ever higher for food is, like so many Darwinian explanations of its kind, little more than a post hoc speculation." Hitching is quite correct, but he rebuts a fairy story that Darwin was far too smart to tell - even though the tale later entered our high school texts as a "classic case" nonetheless.

[T]his theme of mutually invisible life at widely differing scales bears an important implication for the “culture wars” that supposedly now envelop our universities and our intellectual discourse in general […]. One side of this false dichotomy features the postmodern relativists who argue that all culturally bound modes of perception must be equally valid, and that no factual truth therefore exists. The other side includes the benighted, old-fashioned realists who insist that flies truly have two wings, and that Shakespeare really did mean what he thought he was saying. The principle of scaling provides a resolution for the false parts of this silly dichotomy. Facts are facts and cannot be denied by any rational being. (Often, facts are also not at all easy to determine or specify—but this question raises different issues for another time.) Facts, however, may also be highly scale dependent—and the perceptions of one world may have no validity or expression in the domain of another. The one-page map of Maine cannot recognize the separate boulders of Acadia, but both provide equally valid representations of a factual coastline.

If the resident zoologist of Galaxy X had visited the earth 5 million years ago while making his inventory of inhabited planets in the universe, he would surely have corrected his earlier report that apes showed more promise than Old World monkeys and noted that monkeys had overcome an original disadvantage to gain domination among primates. (He will confirm this statement after his visit next year—but also add a footnote that one species from the ape bush has enjoyed an unusual and unexpected flowering, thus demanding closer monitoring.)

A hot topic of late, expressed most notably in Bernie Siegel's best-selling books, has emphasized the role of positive attitude in combating such serious diseases as cancer. From the depths of my skeptical and rationalist soul, I ask the Lord to protect me from California touchie-feeliedom.

Since the universe must contain millions of appropriate planets, consciousness in some form - but not with the paired eyes and limbs, and the brain built of neurons in the only example we know - may evolve frequently. But if only one origin of life in a million ever leads to consciousness, then Martian bacteria most emphatically do not imply Little Green Men.)

Evolving life must experience a vast range of possibilities, based on environmental histories so unpredictable that no realized route - the pathway to consciousness in the form of Homo sapiens or Little Green Men, for example - can be construed as a highway to heaven, but must be viewed as a tortuous track rutted with uncountable obstacles and festooned with innumerable alternative branches. Any reasonably precise repetition of our earthly route on another planet therefore becomes wildly improbable even in a trillion cases.

I have long recognized the theory and aesthetic of such comprehensive display: show everything and incite wonder by sheer variety. But I had never realized how powerfully the decor of a cabinet museum can promote this goal until I saw the Dublin [Natural History Museum] fixtures redone right. […] The exuberance is all of one piece—organic and architectural. I write this essay to offer my warmest congratulations to the Dublin Museum for choosing preservation—a decision not only scientifically right, but also ethically sound and decidedly courageous. The avant-garde is not an exclusive locus of courage; a principled stand within a reconstituted rear unit may call down just as much ridicule and demand equal fortitude. Crowds do not always rush off in admirable or defendable directions.

Lernaeodiscus porcellanae turns control of the host into a fine art. After castration by the parasite, male crabs develop female characteristics in both anatomy and behavior, while females become even more feminized. The emerging externa then takes the same form and position as the crab's own egg mass... The crabs then treat the externa as their own brood. In other words, the parasite usurps all the complex care normally invested in the crab's own progeny.

Darwinian natural selection only yields adaptation to changing local environments, and better function in an immediate habitat might just as well be achieved by greater simplicity in form and behavior as by ever-increasing complexity.