I’m not going to aim a abstract of the week’s actions right here. That was the unenviable job given to Roberta Millstein, and maybe a future edited quantity will comprise a elegant model of her remarks. There may be one job I can’t sidestep nevertheless. Historic contingency. Now what precisely is that? If I let you know that we didn’t resolve the problem over per week of debate, you’ll hardly fall out of your chair. Nonetheless, it’s value lingering on the query for a second.
To say that one thing—an occasion or final result—is traditionally contingent is to say, no less than, that it might have been in any other case. It might have been the case that no roads in Woods Gap have been named for Chicago biologists. Or that no such place as Woods Gap ever existed. (Think about if the Laurentide Ice Sheet had not reached modern-day Massachusetts. Then there can be no such factor as Cape Cod, and no Woods Gap both.) One thing that might not have been in any other case will not be contingent, it’s crucial. It’s true in all attainable worlds, in case you’re into that form of factor.* A contingent final result is true in solely some attainable worlds. I’m being a bit sloppy right here, however the primary level should be clear. Contingent outcomes are distinct from crucial ones. That is what we would name a “minimal sense” of contingency.
[* Actually, the things that are supposed to be true in all possible world are necessary truths: truths of logic, say. In discussions of contingency in evolution, the sense of necessity in view is different. It refers to “physical necessity,” or something like that: the kind of necessity underwritten by laws of nature. Something that is physically necessary in our world will not be physically necessary in all possible worlds—it will only be necessary in those worlds whose laws of nature resemble our own.]
Minimal contingency is all properly and good. However particularly in discussions of contingency in evolution, the time period “contingency” carries an whiff of improbability. It’s not simply pointless that there are two streets in Woods Gap named after Chicago biologists. It is usually unlikely, contingent on a slew of historic particulars lining up good. Had one or just a few of those particulars been misaligned, then the result would have didn’t acquire and one other, fairly completely different one would have taken its place. To label an final result “contingent,” then, is to attract consideration to the sequence of distinctive occasions (or “contingencies”) required to carry it about—it isn’t simply to flag that it might have been in any other case.
Discussions of contingency within the life sciences are most likely as previous as biology itself, however relating to discussions of contingency per se, an necessary touchstone is Fantastic Life. That is the ebook that Stephen Jay Gould printed in 1989. It’s maybe greatest remembered for popularizing the expression “replaying life’s tape,” which additionally equipped the title for our seminar. The related thought experiment runs as follows. Think about you’ll be able to “rewind the tape of life” and play it once more from scratch. Throughout this “replay,” the historical past of life as you understand will probably be erased and written over with one thing new. However what precisely? How intently will this new historical past of life resemble the previous one, each in its broad contours and its intimate particulars? And—since one element pursuits us most of all—how doubtless is it that human-like intelligence will evolve anew? Gould’s reply to the final query is, “not very.” In truth, “any replay of the tape [will] lead evolution down a pathway radically completely different from the street truly taken.” Evolution is a historic course of, and the “essence of historical past” is contingency. This implies that human intelligence is a cosmic accident that just about actually wouldn’t reappear if the historical past of life might be run again to the start and allowed to unfold once more below the identical or related circumstances.
There are numerous difficulties concerned in decoding what Gould is as much as. I’m not going to rehearse these right here (for these within the particulars, I like to recommend that you simply try John Beatty’s put up from 2017, which I just lately re-posted in honor of the seminar). As an alternative, I wish to take into account a difficulty that didn’t come up throughout our discussions at MBL. That’s: simply how efficient is Gould’s argument anyway? By this I don’t imply how efficient is it scientifically. Gould’s argument is a scientific argument—it’s an argument that the historical past of life would unfold very in another way if the “tape of life” might be run once more from the Cambrian radiation. (The entire thing is strung along with gossamer threads of instinct, however that isn’t my concern right here.) No, what I’m serious about is how efficient the argument is as a broadside in opposition to anthropocentrism—the view that people are crucial issues on this planet.
As Derek Turner advised on the seminar, a central purpose of the “replay experiment” is to undermine anthropocentrism by severing its connections with evolutionary principle. Gould takes it to be a comforting thought that people are the inevitable results of a progressive evolutionary course of: a course of that, left to its personal units, was certain to supply one thing like a human thoughts. The replay experiment seeks to problematize this by displaying that people are completely unintended. Take one unsuitable activate the evolutionary path resulting in people and bam!—not solely are people erased from the next historical past of life, however so is the most effective probability of manufacturing something resembling a human thoughts. (Gould actually thinks this. The final pages of Fantastic Life stroll readers via a collection of counterfactual situations. What if the eukaryotic cell hadn’t come collectively? What if the Ediacaran biota hadn’t gone extinct? What if a unique set of anatomical designs had swum via to the Ordovician Interval? And so on. At every check-point, the unrealized risk erases people—and I collect, something resembling a human thoughts—from the next historical past of life.)
All this has the specified impact of creating human minds appear removed from inevitable, and certainly next-to-miraculous. However isn’t this maybe a little bit of an issue? Perhaps Gould is true that some individuals take solace in the concept human minds emerged inevitably from a progressive evolutionary course of. I can think about a liberal theologian from the early a part of the 20th century taking this view. (Why did God arrange the universe in the way in which He did? As a result of He knew it was certain to supply human-like minds of their multitudes.) Nonetheless, I submit that what’s extra conducive to human vanity is the notion that people are simply further particular issues. Maybe we’re unbelievable—okay, fantastic—but when the reason being that one thing so completely distinctive is tough to tug off, then human vanity escapes unscathed. Ask your self, which of those is extra damaging to anthropocentrism: the notion that we’re unbelievable as a result of our defining characteristic is extremely troublesome to evolve, or the notion that we’re odd merchandise of evolution, brainy however not miraculous? Gould opts for Door A, and, I believe, stubs his toe on the way in which via.