There are tendencies on both sides of this argument to fail to clearly establish what this and the rest of science actually says and means--when fairly integrated into a coherent statement that does not overlook or simplify facts to the point of error. It requires clarity and accuracy to do this. Knowledge and understanding, some useful degree of skill and experience, adherence to valid logic, and a reverence for truth are all part of the overall challenge that completes for 'fair treatment'. This is obviously not a PhD seminar in evolutionary biology, so we need to avoid blending too much pop science with the real thing. Most of us would agree that clarity and accuracy are minimum prequisites to achieving that.
My suggestions on both sides of the arument are to try to be careful with the definitions of terms, and to rely more on the actual content of what the authorities say, and less on the paraphrasing what they said. We need to be careful to not overlook the many things they have published to further their own aims of accuracy and clarity. In Gould's case, that includes some refinements to his many statements over 30 years of extensive writing on this subject. He obviously didn't just keep repeating himself -- if his 1980 conference were that central to his theory, he would have just re-published it over and over, and it would be required reading to get a degree in science. But he didn't, and it isn't. He had much more to say - and there is reason for that - and those reasons haven't really been brought forward here. Similarly Ayala would not have retracted Lewin's characterizations of his 1980 remarks if he felt they were central to his position. Further, if Ayala fully agreed with Gould he would not have partly discredited Gould for, among other things, making apparently contradictory statements and/or retractions over the years along with his many expansions and refinements to what his original 1972 thesis said. In short, Gould's lifetime pursuit of explaining the fossil record was a work in progress. In neither began nor ended in 1980.
Here is Ayala describing Gould's own analysis of the question of 'gaps'. This is just a fragment of the many details needed for clarity and accuracy; the devil is in the details. Here I pick up on a discussion of uniformitarianism, which runs counter to the punctuated equilibria in the strata themselves, as follows:
Uniformitarianism interprets geological history as caused by more-or-less steady forces of nature. This theory was forcefully argued by James Hutton (1726 – 1797) and particularly by Charles Lyell (1797 – 1875), who had considerable influence on his younger contemporary, Charles Darwin. The French comparative anatomist and paleontologist, Georges Cuvier (1769 – 1832) rather argued that only the occurrence of catastrophic events could account for the sharp discontinuities observed in the geological record. It is now commonly accepted that the impact of a kilometer-wide meteor on the Yucatan peninsula caused, at least in part, the mass extinctions associated with the K-T event. However, extensive efforts have failed to discover similar extraterrestrial agencies as causes of other mass extinctions that occurred in the geological history of the Earth, some of which, such as at the transition between the Permian and Triassic periods, were even more extensive than the K-T event.
Franciso J Ayala
"The Structure of Evolutionary Theory: on Stephen Jay Gould’s Monumental Masterpiece"
Theology and Science, Vol. 3, No. 1, 2005
Franciso J Ayala
"The Structure of Evolutionary Theory: on Stephen Jay Gould’s Monumental Masterpiece"
Theology and Science, Vol. 3, No. 1, 2005
One of my first arguments against the notion that there should only be "slow and steady" forces acting on nature, just as there "should" have been a uniformity of stratification, is that Uniformitarianism was merely a stage in understanding nature. It was superseded by newer and more complete evidence and better analysis. The thorn in the finger of modern universal Uniformitarianism, as it has been applied to Gradualism here, is the simple fact that extinction events represent any number of collapsing ecosystems for any number of causes that remain to be explained -- but which probably have little or nothing to do with the reasons that gradual differentiation (whether by genetic drift, adaptive radiation, or natural selection under slow onset of catastrophe) proceeds as the default process under more mild and "normal" conditions -- and the understanding and refinements to this that define science no differently than in any other field of discovery.
The same is true for stasis. Neither condition undermines the central tenets of Darwin's original theory. Stasis is one of the permutations for all of the ways things can happen, just as sometimes the laws of physics, thermodynamics, chemisty, genetics, system engineering or economics will encounter the "causes" and nature of any other kind of equilibrium. I think you will see the threads of this logic woven all throughout evolutionary biology, while gradualism remains intact. They are not entirely mutually exclusive, and modern textbooks will tend to explain this although some here may be arguing against what they learned in Paleozoic era of their lives, from books which have long since been updated. It's just that, since focusing on this has little to do with understanding natural selection in the popular experience (such as noting the replacement of niches once occupied by tigers with niches favorable to pigeons, ants and cockroaches) educators will carry the torch for best evidence, and the best science to explain it. That's a principle that's hard to refute.
But also, let's be fair about our own experiential bias. While we live in an age in which ecosystems are crashing rapidly, we may tend to think of them -- say over a lifetime - as gradual. It's merely a question of scale. And there is no universal yardstick to say that one particular crash is too fast or too slow to comport with some proprietary notion of how Nature might work. It is what it is, and we either try to reconcile it against our expectations and beliefs, or we don't. Fortunately we also live in an age replete with tools which simplify our quest for reconciliation. The real question here is: are we using them? That's probably more at the core of this discussion than anything else. Like any other branch of science it's a very complex body of knowledge. Aren't we oversimplifying it here?
