Geology As A Socially Embedded Science

C.P. Rajendran writes on geology as a socially embedded science, and traces its historical development from a tool to exploit natural resources to present day concerns about sustainability.

"The bottom line of the arguments is that geology fortified by its unique narrative power and reasoning prowess which are the hallmarks of all historical sciences, cannot be seen from the perspectives of physics nor should it be treated as a derivative science. Geology is a ‘preeminent example of a synthetic science’, wherein the geologist employs a suite of logical techniques and tools to understand nature and its components. And, such reasoning powers that depend on the classical hermeneutical methods or interpretative logical procedures offer far superior methodology to find answers in a world of complexities and uncertainties that we now inhabit, be it safe disposal of nuclear waste, climate change or receding groundwater levels".

Fine essay. Do read.

Open Access.

Before Darwin: Dante Alighieri On Language Change

My Book Shelf  #21

I came across this passage in Empires of the Word: A Language History of the World by Nicholas Ostler. The topic is the change of Latin in to various Romance languages post demise of the Roman Empire in Europe:

The first theorist of these new linguistic developments is none other than the leading Italian poet, Dante Alighieri, who lived from 1265 to 1321. In his De vulgari eloquentia he recognized that Latin, grammatica, was in essence the preserved older form of the Romance languages. He seems to have had as much difficulty in convincing his audience that these ancestral differences were the predictable result of gradual change as Darwin was to find with a different subject matter and timescale, five centuries later.

Nor should what we say appear any more strange than to see a young person grown up, whom we do not see grow up: for what moves gradually is not at all recognized by us, and the longer something needs for its change to be recognized the more stable we think it is.  So we are not surprised if the opinion of men, who are little distant from brutes, is that a given city has existed always with the same language, since the change in language in a city happens gradually only over a very long succession of time, and the life of men is also, by its very nature, very short....

The italicized portion is Dante Alighieri's analysis.

So then how do we know that a particular language has descended from an older language or that two languages are sister languages, both having evolved from an older language? And the same could be asked of species. How do we know that two species are related and evolved from a common ancestor? 

How Do We Know Fossils Were Once Living Organisms?

In the September issue of Geology there is a good give and take (open access) on the origin of early Neoproterozoic carbonate rock textures. The debate revolves around an interpretation made by Neuweiler et al. (2009) that certain cement filled cavity and mud textures in Neoproterozoic carbonate bioherms (carbonate mounds formed by aggregating and colonial organisms) look very similar to younger sponge replacement fabrics found in Palaeozoic and modern bioherms.

Even though there is no recognizable fossil sponge body parts in the studied Neoproterozoic carbonate (little Dal reefs, Canada)  the authors interpret the diagenetic fabric as indicative of a metazoan origin (they say they cannot conclusively link it to any specific sponge taxon) pushing in their view the geological evidence for multicellular animals to around 875 million years ago. This is about 200 million years older than what most scientists acknowledge. Noah Planavsky in the comment section disagrees about the metazoan origins of the texture and suggests that microbiota can also form similar fabrics.


I found the study interesting in itself. I have worked with some pretty complex diagenetic fabrics and it is always a challenge to tease out components that are purely inorganic from those that have a biogenic origin.

I feel though that a study like this fulfills another important role in science - it is of epistemological value. I used to help my PhD adviser with the paleontology exhibit on Science Day at the local mall in Tallahassee and we had people coming up to us and asking " ...but how do you know that this fossil was once a living creature...?"

A study like this tells us about the methodology and chains of reasoning scientists use to gather a body of knowledge about how fossils form. In this case the authors compared sponge remains from modern bioherms with older and older deposits. In the modern bioherms the sponge organism had died relatively recently and the organic tissue and other skeletal parts were still joined together as a coherent organism. Some organic material had degraded and in its place were tiny carbonate crystals. In some internal body cavities carbonate mud had accumulated forming a sort of a cast of the body part. This is a clear indication that as organic material degrades its place is taken up by inorganic material which retains the same shape as the organic matrix.

The researchers then went further back in time and looked at Cretaceous and Paleozoic rocks. In these samples there was no organic matter, that had decayed away long back,  but other typical sponge skeletal hard parts like spicules were still preserved and recognizable as sponge remains. The shape and form of the interior of the sponge the characteristic canal system was now completely filled by cement and mud. So although there was no coherent organism with linked body parts the association of spicules with a cement and mud filled connected cavity system which had a shape just like the canal system of the sponge gives us confidence that we are looking at sponge fossil fabrics.

One can then go one step further as the authors have done and interpret fabrics with characteristic shapes but no sponge remains (no spicules or anything) as having formed by the alteration of a large multicellular creature. That specific interpretation may be right or wrong in this case but that's the way scientists "know" that fossils were once living creatures. It's a good example to use to explain - How do we know what we know?