The Earth has had a dramatic history—the rise and fall of continents, of seas and of bewildering diversities of life; dramatic shifts in climate, in the composition of the air, and in patterns of biotic exchange. These changes are often global and are often recorded in rock. Have a look at these distinctive sandstone deposits from outside of Sydney:
The Permian period is coal-rich, marked by thick black rock. This ends abruptly as we lead into the Triassic. The division between the Permian and the Triassic also marks an astonishing historical event: the most severe mass extinction (something like 96% of the world’s marine species bite the dust). This all happened over two hundred and fifty million years ago, but—with the right knowledge—can be gleaned from an examination of the rocks they left behind.
Geological divisions, the names splitting strata, then, require either a clear marker dividing two stone patterns from another, or a dramatic historical event. Preferably both. The ‘great dying’ which marks the Permian-Triassic split is just such a case. Changes in mineral deposits (a lack of coal) and to the fossil record (the disappearance of some plants and animals and the appearance of new sorts of fossils) make for an observable, measurable and geologically meaningful division between two periods.
In the last hundred thousand years or so a new and quite unique force has begun shaping the planet: ourselves. Humans conduct controlled burning, domesticate some animals and hunt others to extinction, plant crops, build cities, burn coal and battle one another. We are, as Carlos Santana has put it, “significant geological agents”. But are our activities sufficient grounds for a new geological epoch? Has human activity taken us from the Holocene to the Anthropocene?
The Anthropocene is supposedly a new geological epoch coined by Paul Crutzen (a chemist) almost twenty years ago. It is a big deal in political, conservation and humanistic circles. But should it be a big deal for Earth Scientists? Santana argues not:
Geologists have a different perspective from conservationists and political actors (not to say that geologists cannot or should not be conservationists and political actors as well!), and forcing formal geological recognition of the Anthropocene acts against both of those interests, or so argues Santana.
Santana’s arguments are based on a division between two perspectives: a synchronic perspective and that of the future geologist.
The Anthropocene would be unique as a geological epoch because it requires the perspective of the ‘future geologist’: as opposed to being identified historically based on changes which have in fact happened to mineral deposits, the Anthropocene would be identified based on predictions about the changes that are currently being made to deposits—strata that are right now in the process of being lain down—and its legitimacy would depend upon that pattern continuing into the future. For Santana, predicting future strata rather than explaining past strata or predicting where minerals will be found based on past strata is a quite different ballgame: “understanding the future geologist’s perspective on a possible Anthropocene certainly requires tools not traditionally found in the geologist’s toolkit.”
From a synchronic perspective, the identification of the Anthropocene matters for its political effects—that it will lead to behaviour changes in current human society, hopefully helping to advert the kinds of ecological, climatological and social disasters that, well, we seem to be careening towards.
Santana argues that, for any putative Anthropocene markers, the future geologist will run into trouble either because (1) future human action could stop the effects which generate the markers, (2) the processes continue from the Holocene, or (3) they are too local. What about the synchronic perspective? Santana doesn’t think we should worry too much about mixing politics and science. He points out that objections claiming we shouldn’t mix scientific and political judgment are likely to lean on the kind of value-free ideal that philosophers of science have convincingly rejected. Santana instead points out that the folks who hold out against climatic tragedy already deny scientific consensus: there’s little reason to think that the voices of Earth Scientists would somehow be the convincing straw to break the back of the science-denying camel.
So, whether you hope the Anthropocene will motivate (extremely necessary) political and social action, or whether you are after objective divisions in strata, you should reject formal recognition of the Anthropocene.
Derek Turner writes…
I think I agree with Santana’s conclusion that a formal scientific ratification of the idea that we’ve entered a new geological epoch—the Anthropocene—would be premature. However, there is another line of argument that gets us to the same conclusion, an argument that involves reflection on the weirdness of history.
In his work on the philosophy of history, Arthur Danto pointed out that many statements about the past are really weird. (He called them “narrative sentences,” though what you call them doesn’t matter much.) Here are a couple of examples:
(1) World War I began in August, 1914.
(2) Derek’s parents got married in 1967.
These statements are both true, full stop. They are objective facts about the past, if anything is. But if a journalist living through the events of August, 1914, had written that World War I had just broken out, the statement would have been unintelligible. The assassination of the Archduke Franz Ferdinand in 1914 did not become the beginning of World War I until decades later, with the occurrence of a second world war. The same weirdness occurs with statement (2). It’s true that Mary Winters and Elmer Turner got married in 1967, but that event didn’t become the marriage of my parents until much later, when they became my parents. According to Danto’s analysis, what makes sentences like (1) and (2) weird—and distinctively historical—is that they contain a double reference to different times. For example, statement (1) is about events in 1914, but it also contains an implicit reference to a later world war. Statement (2) is about something that happened in 1967, but makes reference to a person who wasn’t born until 1974.
One might be tempted to read Danto as making a narrowly epistemic point. One possible view is that statement (1) was in fact true in 1914; it’s just that no one at the time was in a position to appreciate its truth. The only way for someone in 1914 to evaluate statement (1) would be to try to inhabit the “future historian’s perspective.” This epistemic framing is the one that Santana uses to craft his first argument about the Anthropocene. Has a new geological epoch begun? Maybe, but the only way for us to assess that claim is to try to inhabit the future geologist’s perspective. And that’s difficult to do, for the reasons he adumbrates. So there might be compelling epistemic reasons to wait (and for quite a long time!) before making certain sorts of historical claims about the moment we are living through.
Danto’s own argument, though, is a bit more radical than this narrow epistemic framing would suggest. The problem is not just that in 1914, no one was well positioned to say whether claim (1) is true. The problem is that in 1914, there was simply no determinate fact of the matter about whether WWI had begun. Whether the events of August 1914 would count as the beginning of World War I would depend on how things play out in future decades. Would there be another great war, with the same major players? Similarly, in 1967, there was no determinate fact of the matter about whether my parents had gotten married. Sure, two people were married, but whether that wedding was the wedding of my parents would depend on how things played out later. This is the genuinely weird, even mindbending thing about history: Often the facts about what’s happening only get established retroactively, depending on what happens downstream.
This insight goes back a long way in western philosophy. For example, Aristotle is famous for exploring the strange-sounding suggestion that the goodness of a person’s life might depend on things that unfold after that person’s death. In Chapter 11 of the first book of Nichomachean Ethics, he writes that “the good or bad fortunes of friends, then, seem to have some effects on the dead.” One reason for this, perhaps, is that our lives are historical: some of the facts about what we do may only get established retroactively, depending on how things play out after we die—on how well things go for our friends, on whether others carry our life projects to completion, etc. By analogy, one might wonder whether the meaning of what humans are doing on Earth may not become fully determinate until after humans are extinct.
Danto’s work has had very little uptake among philosophers of science. One philosopher who’s drawn some inspiration from Danto is Marc Ereshefsky, who has defended a Danto-esque view of speciation. Ereshefsky argues (here) that whether certain biological events—say, a founder population getting stranded on an island—are speciation events actually depends on what happens later on downstream. I agree with Marc about this (actually, we run with this idea a bit more in this recent collaborative paper). But I also wonder if this Danto-esque point might apply much more broadly – say, to discussions of the Anthropocene.
Indeed, I wonder why Santana does not make the Danto-inspired claim that there is simply no determinate fact of the matter about whether we are living at the beginning of a new geological epoch. Whether this is indeed a new epoch will depend on what happens down the road, over the next thousands, or even tens or hundreds of thousands of years. And who knows, maybe in the not-so-distant future our robot overlords will have a good laugh at the idea that those silly and vain humans thought this new geological epoch was all about them. If geological time intervals are essentially retrospective, then the effort to formally mark the commencement of a new one while it is happening looks like something of a category mistake. Of course, this line of reasoning just lends further support to Santana’s thesis that it’s really too soon to say whether this is the Anthropocene. But the argument is not merely epistemic; it’s an argument about the weirdness of history itself.
Danto, A.C. (2007). Narration and Knowledge. New York: Columbia University Press.
Ereshefsky, M. (2014). “Species, Historicity, and Path Dependency,” Philosophy of Science 81: 714-726.
Adrian Currie writes…
I’m not sure I agree with Santana or Derek on the nature of geological divisions—or at least I’m interested in exploring what happens if we break with a species of assumption both seem to make. Both discussions rely on an asymmetry between past geological divisions and future ones: because future/present divisions rely on tricky predictions which are not independent of our actions (or are simply indeterminate), while those in the past do not, there is something suspect about the future geologist’s perspective. Where I suspect I might want to get off the boat is the implied idea that past geological divisions are (I’m so sorry) set in stone. These divisions too are continually revisable. They are points of ongoing negotiation, which are sensitive to the knowledge states and interests of geologists in various ways. Once we see that past geological divisions are sensitive to both future discoveries, and changes in our knowledge and our interests, I think the future geologist starts to look much less problematic.
The International Commission of Stratigraphy (or ICS) are to blame for officially establishing stratigraphic layers. They often act in the background but sometimes their decisions can be flashpoints for argument. Geologists interested in the Holocene have begun referring to various periods within that block of time (about 11.6k years ago to now): discussing the ‘late’, ‘early’ and ‘middle’ Holocene, for instance. Last year it was decided to divide the era into three subcategories (we’re now in the Meghalayan). This caused a lot of controversy (entertainingly described in The Atlantic), in part because it was perceived as interfering or belittling the notion of the Anthropocene. But the reasons for the three-way split do seem to track Santana’s discussion: each new subdivision has a physical marker (the most recent being an enormous drought in Eurasia). In addition to these markers, the new divisions are motivated by claims and explanations by geologists: the divisions were intended to clarify the meaning of geologist’s claims about the ‘early or ’late’ Holocene, for instance. These two aspects deserve reflection: the divisions recognised by geologists are not interest-independent. What made that Eurasian drought a geological division was that the geologists needed a way of dividing the Holocene. This doesn’t mean that such divisions are wholly constructed or invented by geologists: it is simply that there are many possible legitimate ways of dividing up the geological record, and how this is done is decided in part by geological interests. And indeed whether the divisions work in the long run depend upon how successfully they shape geological research.
With these points in mind, let’s consider again the kind of claim both Turner and Santana’s arguments rely upon: an asymmetry between the past (normal) geologist and the future geologist. In particular, we have Santana’s claim that because future action could affect whether the anthropocene happens or not, the anthropocene is not a good geological division, and we have Turner’s claim that there is no fact of the matter about whether we are in the anthropocene, so the anthropocene is not a good geological division.
Regarding Santana’s claim, I’m not sure why the possibility of some future behaviours affecting a geological division (reducing carbon emissions, say) are the sort which should lead us to reject those divisions, while others (coming to the conclusion that the time-period the division identifies isn’t interesting enough) are not. Regarding that later kind of difference, all geologists are future geologists. There might be a nice way of distinguishing between these, but without such a distinction (and a justification for that distinction’s sufficiency for denying the future geologist their divisions), I think at least that part of Santana’s argument should be rejected.
Regarding Turner’s much stronger version of the asymmetry, I suppose I’m not sure why there not being a fact of the matter regarding something—it not be determinate whether something is true—is reason to not commit to thinking that, if current trends continue, such a thing will come true. This is, in effect, what the Anthropocene-loving future geologist is claiming. Worst case scenario—actually best case scenario!—the bet doesn’t come out right and we later wheel out the ICS to de-confirm the division. After all, past geological eras are also sources of continual negotiation and debate, so I don’t see a reason to think current-and-future focused eras should be any different. Generally speaking, I think the epistemic issues here far outstrip the metaphysical (or linguistic, if we’re keeping close to our Danto-roots) foot Turner puts forwards.
None of this I think undermines Santana’s most pressing points regarding the official identification of the Anthropocene: namely, whether it would actually make a difference (or a positive difference) vis-à-vis pulling ourselves back from various environmental ecological and environmental brinks, and the effects such an official identification would have on current geological practice. Given that ICS recognition is a signal not just of geological knowledge but of the interests of geologists, officially recognising the Anthropocene would also sanction and encourage research (potentially a lot of research) explicitly focused on that geological time period. This matters if—as I think is plausible—the ways geology can inform us about our current predicaments require a much deeper time window than the very recent past. If Santana is right that officially recognising the Anthropocene would refocus geological research away from the Holocene more generally (and other time periods for that matter) this could be a pretty bad consequence. Especially if we follow Santana’s pessimism about the political power geological recognition of the Anthropocene would wield.
Having said this, I think both Turner and Santana give the future geologist a somewhat bum deal, moreover I’m not so sure whether there is as wide a difference between past-strata and future-strata geological divisions as they imply. Moreover, I reckon that future-geological speculation could be a thing worth doing more of and, potentially, incorporating into geological divisions. Even if that involves gloriously ‘cancelling’ the anthropocene sometime down the track.