By Jason Curtis Droboth
March 4, 2020
A short paper for GLGY 699: Philosophy of Geoscience
During a recent winter holiday, in search of some much-needed rest and respite, I tried as best I could to take a load off and ‘do nothing’. However, ‘doing nothing’ quickly turned into ‘something’. A curious mind and busy hands are a hard thing to keep still. I needed a task to keep me busy, to keep me away from ‘just checking my email’ or running errands. Something just difficult enough that it would demand most of my mental focus. Something with a set goal. A goal that, when accomplished, didn’t really matter yet brought with it immense satisfaction. So, I brought out a jig-saw puzzle.
What’s great about jig-saw puzzles is that every piece has a set place. If you put a piece in the wrong spot, even if it fits at first, at some point, something will seem ‘off’. And with each added piece, the image becomes more and more clear. In a way, you slowly reverse the clock, piece by piece, towards the image’s original state. Until you see it as it really was before being split into 1000 pieces.
The aptly named theory of continental drift is simply the idea that continents have moved or ‘drifted’ laterally over time (Giere, 1988). Where the continents exist today, in relation to one another, are not where they have always been. This idea, simple in concept, but profound in its explanatory power, now forms the very foundation of our understanding of historical and modern geology. Once accepted it answered countless conundrums that scientists struggled to answer. But it was only truly accepted by the scientific community between 1965-1975, very late indeed (Giere, 1988)! This may surprise some since a brief glance at a world map makes it glaringly obvious that there are two big ‘puzzle pieces’ that must certainly fit together: Africa and South America. Did scientists not recognize this obvious fit? Were they waiting for more evidence that would merit a logical decision? Which other factors might have caused such a delay in accepting the theory?
I have a specific scientific method for puzzle-building. It rests entirely on pattern recognition. The reason I call my method ‘scientific’ is because I work in a systematic way by objectively grouping pieces according to certain types of patterns I observe, which I then prioritize and solve in order of increasing complexity. The characteristics can be organized into 2 major categories. First, and most obviously is puzzle piece shape. I look for pieces that must belong on the edge since they have at least one side that is perfectly flat. Next, I look at the content of each piece. Within the content category are various sub-categories: colour, patterns that have an obvious directionality (lineations, objects, faces, etc.), and then complex non-orienting patterns. Once I’ve done this, I’ll identify what I see to be the most dominant pattern that best describes a piece and then organize them into groups of similar pieces. Finally, I decide which groups would be easiest to start placing first, not surprisingly, it’s usually the border pieces. I know the flat sides must be oriented outward, then I look for content patterns. Let’s say there are only 3 red border pieces, I’m going to assume that they must exist in the same location. So I try to put the 3 red border pieces together based again on shape patterns.
The most obvious evidence in support of Alfred Wegener’s continental drift theory, and his original source of inspiration, were shape patterns. The outer shape of Africa’s west coast and South America’s east coast are surprisingly congruent. From a quick glance at a map they just look like they should fit together. But is this enough evidence to prove such a claim? After all, this idea implies that 2 huge solid continents, full of rocks, metals, water, animals, and everything else, moved laterally thousands of kilometers! Many puzzle pieces fit together if you push hard enough. But do the content patterns match up?
“It is just as if we put together the pieces of a torn newspaper by their ragged edges, and then ascertained if the lines of print ran evenly across. If they do, obviously there is no course but to conclude that the pieces were once actually attached in this way. If but a single line rendered a control possible, we should have al- ready shown the great possibility of the correctness of our com- bination. But if we have n rows, then this probability is raised to the nth power” (Wegener, 1966).
Through analogy, we see Wegener explaining his process of using shape and content patterns to match up pieces that were once connected. He thought that the more patterns that lined up, the more confident one could be that the pieces once fit together. Wegener looked first to shape patterns, then to the content category and its various sub-categories: paleoclimatology, geology, and paleontology.
According to Giere, At the time “it was fairly well established that there had been ice caps with considerable glaciation in South Africa, South America, India, and Australia-areas that are now temperate or warmer” (Giere, 1988). Wegener saw this as evidence in favour of ‘mobilization’, the idea that continents can, have, and do move laterally (Wegener, 1966). A necessary assumption for his explanations. What’s more, it suggested to him that glaciated areas were likely closer to the polar regions. When I find a blue puzzle piece, I might recognize that it resembles a blue sky. Since I know the sky is above the ground, I assume that the puzzle piece belongs at the top of the puzzle.
In his book The Origin of Continents and Oceans Wegener presents a vast array of geologic congruences between now distant continents or islands (1966). Like the terrestrial “Old Red” deposits which are found not just across the East coast of North America, but also in Greenland and Spitsbergen. “In their sum-total” Wegener says, “these discoveries give a picture of an area, united and continuous at the time of deposition, which to-day is broken up…” Many geologic formations in South America, like the so-called “Brazilian Complex”, matched the complex lithology, structure, and sequences of formations in Africa, like the “Fundamental Complex”. Again, when two puzzle pieces appear to lock together, the fact that they’re of similar colour and with the same complex ‘non-orienting’ patterns, would give me further confidence that they do indeed belong together. But I would also seek ‘orienting structures’ like a series of parallel lines which, if the two puzzle pieces did indeed belong together, should match up. Wegener also looked towards a host of correlations in the orienting structures. Strikes, dips, folds, faults, and more. For example, he notes that the general strike directions in South America matched that of Africa. In fact, he claimed that if the continents were rotated to fit, the Amazon and Niger rivers, which generally follow the strike of the beds, would be parallel to one another.
It was generally accepted at the time that many dozens of extinct flora and fauna lived on both the African and South American continents. Fossil records showed that terrestrial plants like Glossopteris and animals like Lumrbicus lived on both continents at the same time (Wegener, 1966). But a popular explanation for distribution this was a land bridge, a piece of land between the two continents which has since been submerged by the ocean. Wegener again saw this as further proof that the two puzzle pieces which seem to fit together, and whose colours and patterns matched, did indeed belong together (Wegener, 1966).
I previously referred to my puzzle-building method as ‘scientific’ because it was based on systematic observations and objective categorizations. But is my puzzle building method really scientific? Well, this depends on how one defines ‘science’. Scientific or not, it works. I’m very good at making puzzles. So maybe instead of asking “is it scientific?” I should really ask “why and how does my process actually work?” This approach to understanding the scientific method or process was made famous by Thomas Kuhn.
Kuhn examined how science has happened throughout history, seeing it holistically as a social process governed by key trends. First, the majority of science is dominated by stable paradigms and normal science. Most of the time, most scientists are doing normal science within the stable framework of the dominant paradigm in their disciplines. The paradigm, which Kuhn saw as “universally recognized scientific achievements that for a time provide model problems and solutions to a community of practitioners”, provides frames of reference and direction for scientists (Kuhn, 1996). Without these paradigms science could not exist as a social activity, since no scientists could speak the same scientific ‘language’. And no individual scientist would know where to look, what questions to ask, or how to answer them. In a way, paradigms provide scientists rules they can trust and a general picture of what picture they’re trying to create.
When I work on solving a jigsaw puzzle, I work within what might be called a paradigm. First of all, there are rules I can trust. I trust that each piece is there and belongs only to that puzzle. Most importantly, I already know what picture I’m trying to create. It’s right there in front of me on the box. I trust that with the final piece in place, the puzzle will reveal an image that is nearly identical to that on the box, blue sky at the top, sand at the bottom, a cactus standing up straight. It would make no sense to refer to a random photo as a guide, nor should I use pieces from other puzzles, nor should I place some of the pieces image-side down. So how does this compare with Wegener’s process?
I would argue that the paradigm at Wegener’s time was, at the highest level, one grounded in uniformity, specifically ‘lateral stabilism’. This painted a picture of the continents as more-or-less stable, or at least, one where only vertical forces over long periods of time could produce many of the dramatic geologic features we see. When Wegener would argue his case for continental drift, like he did at a 1928 symposium, to many scientists it was as if he was speaking another language (van Waterschoot van der Gracht et al., 1928). By this I mean that the rules he was proposing, and indeed the model he was using, might render all their past work useless and flat out wrong. Imagine if I had been building a puzzle, working on it for a very long time, and although I was struggling, I was making progress. Then someone comes along and tells me that the puzzle was placed in the wrong box, I have been referring to the wrong photo all along. Oh and some of the pieces may be from another puzzle. Oh and it’s actually supposed to be a 3 dimensional puzzle! What should I do? Do I believe them and accept the fact that I have wasted all this time working under false assumptions? Or do I dismiss their statements and continue on, after all, pieces are fitting! This is what Kuhn called a crisis.
When new evidence cannot be interpreted within the existing paradigm, known as anomalies, it causes some pressure. If that pressure continues to build without release, a crisis might occur. During this period, scientists begin to examine the paradigm itself, rather than through it. Kuhn saw this as being an event which can precipitate into a revolution during which a new paradigm must quickly fill the void, or else the science stops (Kuhn, 1996). As I continue to build my puzzle, I realize that something is seriously wrong. The pieces are no longer fitting. I need to stop and find out what’s going on before proceeding. A similar situation occurred during what I see as the continental drift crisis. Many years after Wegener’s death, a major scientific revolution occurred which heralded in a new paradigm of ‘lateral mobilism’ where continental drift reigned (Giere, 1988). So why did this take so long?
Few people would disagree that Wegener’s theory of continental drift changed the Earth Sciences forever, however, many would claim that this was a ‘progressive’ change which added a clear stepped improvement to scientific knowledge. From a Kuhnian perspective, this is an incorrect historical narrative. What actually happened was a ‘revolution’, “those non-cumulative developmental episodes in which an older paradigm is replaced in whole or in part by an incompatible new one” (Kuhn, 1996). ‘Lateral mobilism’ and ‘lateral stabilism’ are mutually exclusive paradigms. Accepting one necessitates rejecting the other. It is not a linear accumulation of data, ideas, theories, and practices, but a destructive one which rejects many components of the old paradigm. But destroying an existing paradigm requires a certain critical mass, not necessarily of data but of personalities. This is why it took around 40 years for Wegener’s theory of continental drift to gain mass acceptance and define a new paradigm.
Before I was approached by an outside voice claiming that the paradigm, I was using to build my jigsaw puzzle was wrong, I was quite satisfied with the progress. It was the social pressure of that outsider that got me thinking, however, the implications of their claims were troubling. I would have to define a new paradigm and then start from scratch! So I continued on, the person was after all an outsider. But what if I was building the puzzle with a few other friends? Each of them begins voicing their concerns with our progress. Maybe the pieces weren’t fitting. Maybe they were getting bored. Maybe they trusted the voice of the outsider. Regardless of the motives, progress on the puzzle would stop only if enough people had stopped believing in the paradigm. It is after all a social activity. I believe that, from a Kuhnian perspective, this is what best explains how the Wegenerian revolution occurred and why it took so long.
According to Wegener and some of his colleagues, there was indeed sufficient evidence to support the rational acceptance of continental drift. But it was stopped in its tracks until the 50s and 60s for a multitude of reasons, the most significant of which, I believe, was Wegener’s untimely death. Since science is ‘done’ by people, Kuhn explained the process by which a new paradigm replaces an existing one, in terms of the critical mass of influential and motivated scientists keen on furthering the new paradigm. If the supporters “are competent, they will improve [the paradigm], explore its possibilities, and show what it would be like to belong to the community guided by it” (Kuhn, 1996). It’s initial acceptance depended on competent individuals to push forth its case in a persuasive way that converted others. While we will never know for sure, if Wegener had not died so soon, his continual pressure might have provided sufficient social momentum to spurn a successful revolution.
This paper has explained how the late acceptance of Wegener’s continental drift theory can be understood from a Kuhnian perspective. The metaphor of a jig-saw puzzle has been used in two ways. First, to explain the methodology and types of evidence Wegener used to argue that some of the continents at one time fit together. Like a jig-saw puzzle. Second, to explain how a paradigm is necessary to and frames normal science and how with sufficient crisis, scientific revolutions may result. While compelling evidence may be a major catalyst for creating new paradigms, since science is a social activity, what’s most important is the influence of the scientists in the debate. In the 1920s the paradigm of ‘lateral mobilism’ challenged that of ‘lateral stabilism’ and overthrew it in a scientific revolution only once enough influential scientists converted. Science, like puzzle-building, is a social activity.
Giere, R. N. (1988). Explaining the Revolution in Geology. In Explaining Science : A Cognitive Approach (pp. 227–277). University of Chicago Press.
Kuhn, T. S. (1996). The structure of scientific revolutions. University of Chicago Press.
van Waterschoot van der Gracht, W. A. J. M., Willis, B., Chamberlin, R. T., Joly, J., Molengraaff, G. A. F., Gregory, J. W., Wegener, A., Schuchert, C., Longwell, C. R., Taylor, F. B., Bowie, W., White, D., Singewald, J. T. J., & Berry, E. W. (1928). Theory of continental drift: A symposium on the origin and movement of land masses, both inter-continental and intra-continental, as proposed by Alfred Wegener. American Association of Petroleum Geologists.
Wegener, A. (1966). The origin of continents and oceans. Dover Publications.