Let‘s try to stay grounded: Heated geological debates from history

We often imagine science as a cold, calculated process focused on observations and tangible facts. Well, we would be mistaken: science was not always this way (and in a way still isn‘t). In fact, any scientific interpretation is tainted in some way by the prevailing ideas of its time. As such, studying older scientific theories is a great way to better understand the historical context but also where we are coming from. Maybe no scientific discipline shows that better than geology. Today, I propose to you a quick survey on intriguing parts of our geological study heritage. You‘ll see that looking at and understanding dirt is more complex than you could imagine.

Talking to rocks

Questions about the origin of Earth are not surprisingly as old as history itself. But we need to recognize that systematic study of Earth would be largely ignored for millennia. After all, religions and myths offer satisfying answers already. So why investigate further? Still, some pioneers would consider the subject but at smaller stakes to not offend anyone. Geology would then humbly starts as minerology - the study of rocks and minerals themselves. Mineralogy can be traced back at least to ancient Greece when Theophrastus wrote “Peri Lithon“ (“On Stones“). It deserves a mention that this text is a lapidary. A lapidary is a type of treaty on the properties of stones (mostly when heated in the case of Theophrastus) in verse - that is in a (religious) poem. Later, in the Roman period, Pliny the Elder would expand Theophrastus's work. We would have to wait until the 16th century for the next exhaustive survey of stones and minerals - That would be “De Natura Fossilium“ by Georgius Agricola. Yet, between homages to God and his patron, Agricola would still limit itself to the small scale deliberately omitting the largest rock we know of at the time - Earth. 

Not set in stone anymore

But things would gradually change by first acknowledging Christianity‘s view on Earth. William Whiston‘s “A New Theory of the Earth“ in 1696 would do so. At the time, Christian tradition estimated the Earth to be 6,000 years old. Whiston would support this view and describe in detail the divine creation of the Earth. The most groundbreaking aspect of Whiston‘s work was how he would interpret the Genesis account of creation as being only of the preparation of the Earth for mankind, and not as an account of Earth‘s creation in itself. To Whiston, Earth was shaped by the action of comets and floods (including the one with Noah), both described in the Bible. His arguments were still religious but this was still the first departure from the typical religious view in geological history. In 1779, Comte de Buffon would suggest that maybe, just maybe, the Earth was older than 6,000 years. 6 years later, James Hutton would add the Earth was definitely older than 6,000 years. The floodgates were upon.

Team Aqua vs Team Magma

Here, we reach our first clash of theories. The age of the Earth was incredibly important to both groups as knowing it would help understand HOW stones are made - exactly what those theories disagreed about. James Hutton pioneered that rocks were produced by volcanoes and magma - weathering and erosion leading to deposits on the sea bed. His followers would be called Plutonists (Pluto = Hades). Following in the footsteps of Whiston, Abraham Werner would point out that rock sediments out of oceans. To him, the world started completely flooded, the water level gradually dropping over time letting minerals crystallize. His disciples were called Neptunists (Neptune = Poseidon). Now, we consider both theories to contain a facet of reality - rocks being both made in sea deposits and volcanoes - but to them, it was dog-eat-dog.

Folk rock vs heavy metal

Scientists would not only debate on HOW rocks are made but also how much time that would take. This dispute would be intrinsically linked to the birth of paleontology. The debate was initiated in 1813 by George Cuvier with his “Essay on the Theory of the Earth“. Being of of the first to study fossils in strata of stones, Cuvier observed that fossils did not seem to change gradually over time. Instead, fossils would appear for a specific period and then abruptly disappear. This led him to believe in what would be called catastrophism. Cuvier would propose that all possible animals existed at the beginning of time. Successive and brutal cataclysmic extinction events would filter out species one after the other until we reach what we know today. Opposing him was Sir Charles Lyell. His 1830‘s “Principles of Geology“ would promote the opposite approach. Seeing the slow and methodical weathering and sedimentation processes while working on the field, Lyell would suggest that such slow geological processes are enough to explain how Earth was shaped. This view would be called uniformitarianism and would be quite influential on the successive theory of evolution. Interestingly, Lyell corresponded for many years with Charles Darwin but never truly adhered to his theory of evolution.

Rock solid foundations

At this point, geological disputes were firmly established. As you can see, knowing what we know now, we can‘t fully agree with any of the previous views. Nevertheless, they all encompass some part of the truth. That is the fate of all scientific theories, just less apparent when they are closer to us. Geology would continue its winding way in the 20th century with new approaches and theories more familiar to us (think tectonic plates). But Agricola, Hutton and Cuvier all deserved more recognition in my mind. So, I‘ll stop there for now. Besides, that is quite enough new science for one day - better to stay grounded here.

In any case, see you next time.