33 Stephen Jay Gould Quotes on Biology

Stephen Jay Gould quotes on biology

6. I want to argue that the 'sudden' appearance of species in the fossil record and our failure to note subsequent evolutionary change within them is the proper prediction of evolutionary theory as we understand it. [:] Evolutionary 'sequences' are not rungs on a ladder, but our retrospective reconstruction of a circuitous path running like a labyrinth, branch to branch, from the base of the bush to a lineage now surviving at its top.

8. Each of the major sciences has contributed an essential ingredient in our long retreat from an initial belief in our own cosmic importance. Astronomy defined our home as a small planet tucked away in one corner of an average galaxy among millions; biology took away our status as paragons created in the image of God; geology gave us the immensity of time and taught us how little of it our own species has occupied.

10. I contend that the continued racial classification of Homo sapiens represents an outmoded approach to the general problem of differentiation within a species. In other words, I reject a racial classification of humans for the same reasons that I prefer not to divide into subspecies the prodigiously variable West Indian land snails that form the subject of my own research.

12. For Linnaeus, Homo sapiens was both special and not special. [:] Special and not special have come to mean nonbiological and biological, or nurture and nature. These later polarizations are nonsensical. Humans are animals and everything we do lies within our biological potential. [:] [T]he statement that humans are animals does not imply that our specific patterns of behavior and social arrangements are in any way directly determined by our genes. Potentiality and determination are different concepts.

13. But here I stop-short of any deterministic speculation that attributes specific behaviors to the possession of specific altruist or opportunist genes. Our genetic makeup permits a wide range of behaviors-from Ebenezer Scrooge before to Ebenezer Scrooge after. I do not believe that the miser hoards through opportunist genes or that the philanthropist gives because nature endowed him with more than the normal complement of altruist genes. Upbringing, culture, class, status, and all the intangibles that we call 'free will,' determine how we restrict our behaviors from the wide spectrum-extreme altruism to extreme selfishness-that our genes permit.

14. If you defend a behavior by arguing that people are programmed directly for it, then how do you continue to defend it if your speculation is wrong, for the behavior then becomes unnatural and worthy of condemnation. Better to stick resolutely to a philosophical position on human liberty: what free adults do with each other in their own private lives is their business alone. It need not be vindicated - and must not be condemned-by genetic speculation.

15. Organisms are not billiard balls, propelled by simple and measurable external forces to predictable new positions on life's pool table. Sufficiently complex systems have greater richness. Organisms have a history that constrains their future in myriad, subtle ways.

17. Throughout his last half-dozen books, for example, Arthur Koestler has been conducting a campaign against his own misunderstanding of Darwinism. He hopes to find some ordering force, constraining evolution to certain directions and overriding the influence of natural selection. [:] Darwinism is not the theory of capricious change that Koestler imagines. Random variation may be the raw material of change, but natural selection builds good design by rejecting most variants while accepting and accumulating the few that improve adaptation to local environments.

18. Wallace's error on human intellect arose from the inadequacy of his rigid selectionism, not from a failure to apply it. And his argument repays our study today, since its flaw persists as the weak link in many of the most 'modern' evolutionary speculations of our current literature. For Wallace's rigid selectionism is much closer than Darwin's pluralism to the attitude embodied in our favored theory today, which, ironically in this context, goes by the name of 'Neo-Darwinism.'

19. Hyper-selectionism has been with us for a long time in various guises; for it represents the late nineteenth century's scientific version of the myth of natural harmony-all is for the best in the best of all possible worlds (all structures well designed for a definite purpose in this case). It is, indeed, the vision of foolish Dr. Pangloss, so vividly satirized by Voltaire in Candide-the world is not necessarily good, but it is the best we could possibly have.

21. There is no gene 'for' such unambiguous bits of morphology as your left kneecap or your fingernail. [:] Hundreds of genes contribute to the building of most body parts and their action is channeled through a kaleidoscopic series of environmental influences: embryonic and postnatal, internal and external. Parts are not translated genes, and selection doesn't even work directly on parts.

22. The history of most fossil species includes two features particularly inconsistent with gradualism: 1. Stasis. Most species exhibit no directional change during their tenure on earth. They appear in the fossil record looking much the same as when they disappear; morphological change is usually limited and directionless. 2. Sudden appearance. In any local area, a species does not arise gradually by the steady transformation of its ancestors; it appears all at once and 'fully formed.'

23. Evolution is a theory of organic change, but it does not imply, as many people assume, that ceaseless flux is the irreducible state of nature and that structure is but a temporary incarnation of the moment. Change is more often a rapid transition between stable states than a continuous transformation at slow and steady rates. We live in a world of structure and legitimate distinction. Species are the units of nature's morphology.

27. All versions written for nonscientists speak of fused males as the curious tale of the anglerfish-just as we so often hear about the monkey swinging through the trees, or the worm burrowing through soil. But if nature teaches us any lesson, it loudly proclaims life's diversity. There ain't no such abstraction as the clam, the fly, or the anglerfish. Ceratioid anglerfishes come in nearly 100 species, and each has its own peculiarity.

29. Organisms [...] are directed and limited by their past. They must remain imperfect in their form and function, and to that extent unpredictable since they are not optimal machines. We cannot know their future with certainty, if only because a myriad of quirky functional shifts lie within the capacity of any feature, however well adapted to a present role.

31. A complete theory of evolution must acknowledge a balance between 'external' forces of environment imposing selection for local adaptation and 'internal' forces representing constraints of inheritance and development. Vavilov placed too much emphasis on internal constraints and downgraded the power of selection. But Western Darwinians have erred equally in practically ignoring (while acknowledging in theory) the limits placed on selection by structure and development-what Vavilov and the older biologists would have called 'laws of form.'

32. We do not inhabit a perfected world where natural selection ruthlessly scrutinizes all organic structures and then molds them for optimal utility. Organisms inherit a body form and a style of embryonic development; these impose constraints upon future change and adaptation. In many cases, evolutionary pathways reflect inherited patterns more than current environmental demands. These inheritances constrain, but they also provide opportunity. A potentially minor genetic change [:] entails a host of complex, nonadaptive consequences. [:] What 'play' would evolution have if each structure were built for a restricted purpose and could be used for nothing else? How could humans learn to write if our brain had not evolved for hunting, social cohesion, or whatever, and could not transcend the adaptive boundaries of its original purpose?

40. Our world is not an optimal place, fine tuned by omnipotent forces of selection. It is a quirky mass of imperfections, working well enough (often admirably); a jury-rigged set of adaptations built of curious parts made available by past histories in different contexts. [:] A world optimally adapted to current environments is a world without history, and a world without history might have been created as we find it. History matters; it confounds perfection and proves that current life transformed its own past.

41. We inhabit a complex world. Some boundaries are sharp and permit clean and definite distinctions. But nature also includes continua that cannot be neatly parceled into two piles of unambiguous yeses and noes. Biologists have rejected, as fatally flawed in principle, all attempts by anti-abortionists to define an unambiguous 'beginning of life,' because we know so well that the sequence from ovulation or spermatogenesis to birth is an unbreakable continuum-and surely no one will define masturbation as murder.

42. Siphonophores do not convey the message-a favorite theme of unthinking romanticism-that nature is but one gigantic whole, all its parts intimately connected and interacting in some higher, ineffable harmony. Nature revels in boundaries and distinctions; we inhabit a universe of structure. But since our universe of structure has evolved historically, it must present us with fuzzy boundaries, where one kind of thing grades into another.

45. [A]lthough species may be discrete, they have no immutable essence. Variation is the raw material of evolutionary change. It represents the fundamental reality of nature, not an accident about a created norm. Variation is primary; essences are illusory. Species must be defined as ranges of irreducible variation.

63. [E]volutionists sometimes take as haughty an attitude toward the next level up the conventional ladder of disciplines: the human sciences. They decry the supposed atheoretical particularism of their anthropological colleagues and argue that all would be well if only the students of humanity regarded their subject as yet another animal and therefore yielded explanatory control to evolutionary biologists.

64. When Bonner writes that 'natural selection for optimal feeding is then presumed to be the cause of non-motility in all forms,' I can't help suspecting that some plants might do even better if they could walk from shade to sun-but the inherited constraints of design never permitted a trial of this intriguing option.

81. Biological evolution is a system of constant divergence without subsequent joining of branches. Lineages, once distinct, are separate forever. In human history, transmission across lineages is, perhaps, the major source of cultural change. Europeans learned about corn and potatoes from Native Americans and gave them smallpox in return.

100. I do not think that, practically or morally, we can defend a policy of saving every distinctive local population of organisms. I can cite a good rationale for the preservation of species, for each species is a unique and separate natural object that, once lost, can never be reconstituted. But subspecies are distinctive local populations of species with broader geographic range. Subspecies are dynamic, interbreedable, and constantly changing: what then are we saving by declaring them all inviolate?

102. Bacteria represent the world's greatest success story. They are today and have always been the modal organisms on earth; they cannot be nuked to oblivion and will outlive us all. This time is their time, not the 'age of mammals' as our textbooks chauvinistically proclaim. But their price for such success is permanent relegation to a microworld, and they cannot know the joy and pain of consciousness. We live in a universe of trade-offs; complexity and persistence do not work well as partners.

121. 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).

153. No one should feel at all offended or threatened by the obvious fact that we are not all born entirely blank, or entirely the same, in our mixture of the broad behavioral propensities defining what we call 'temperament.'

154. [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.

160. Complex organisms cannot be construed as the sum of their genes, nor do genes alone build particular items of anatomy or behavior by themselves. Most genes influence several aspects of anatomy and behavior-as they operate through complex interactions with other genes and their products, and with environmental factors both within and outside the developing organism. We fall into a deep error, not just a harmful oversimplification, when we speak of genes 'for' particular items of anatomy or behavior.

161. The vigorous branching of life's tree, and not the accumulating valor of mythical marches to progress, lies behind the persistence and expansion of organic diversity in our tough and constantly stressful world. And if we do not grasp the fundamental nature of branching as the key to life's passage across the geological stage, we will never understand evolution aright.

184. Steve is extremely bright, inventive. He thoroughly understands paleontology; he thoroughly understands evolutionary biology. He has performed an enormous service in getting people to think about punctuated equilibrium, because you see the process of stasis/sudden change, which is a puzzle. It's the cessation of change for long periods of time. Since you always have mutations, why don't things continue changing? You either have to say that the particular form is highly adapted, optimal, and exists in a stable environment, or you have to be very puzzled. Steve has been enormously important in that sense. Talking with Steve, or listening to him give a talk, is a bit like playing tennis with someone who's better than you are. It makes you play a better game than you can play. For years, Steve has wanted to find, in effect, what accounts for the order in biology, without having to appeal to selection to explain everything-that is, to the evolutionary 'just-so stories.' You can come up with some cockamamie account about why anything you look at was formed in evolution because it was useful for something. There is no way of checking such things. We're natural allies, because I'm trying to find sources of that natural order without appealing to selection, and yet we all know that selection is important.

195. The great merit of Stephen Gould's account of the disastrous history of phychometrics is that he shifts the argument from a sterile contest between environmentalists and hereditarians and turns it into an argument between those who are impressed with what our biology stops us doing and those who are impressed with what it allows us to do.