An Annotated Review of Joseph Le Conte’s “Elements of Geology (1896)”: Part 1

Joseph LeConte (February 26, 1823 – July 6, 1901), American geologist, conservationist, and professor at UC Berkeley, made significant contributions to the science of geology following the era of Charles Lyell and Charles Darwin. Importantly, this represents the major shift in scientific thought towards the principle of Uniformitarianism – that the natural processes we observe today have been in effect on the Earth for millennia. This allowed for scientists to make inferences about past events based on their knowledge and observations of current events, or events and processes described by other scientists. It is for this reason I’ve decided to review as much as possible of LeConte’s major work on geology – “The Elements of Geology” – in an attempt to understand 1.) how the science of geology has changed over the past 120 years since the book’s inception and 2.) understand, in general, how scientific thinking has changed over the past century. How did professor’s and scientists formulate arguments, describe complex ideas, develop new theories, and present evidence in age where the computer had not yet been invented? Hopefully this series of posts will shed some light on how scientific thinking and communication strategies have changed over the course of human development.

LeConte begins the Elements with a brief introductory chapter introducing his framework for the study of geology. Here, LeConte outlines the 3 principal departments of geology by using analogies to organic science – what we might today call the life sciences or biological sciences. He relates structural geology to the study of anatomy, dynamical or chemical geology to the study of physiology, and historical geology to the study of embryology or developmental biology. Interestingly though, in the following half of his introduction, he highlights a key difference between the two sciences.

But there are two important points of difference between geology and organic science. The central department of organic science is physiology, and both anatomy and embryology are chiefly studied to throw light on this. But the central department of geology, to which the others are subservient, is history. Again : in case of organisms – especially animal organisms – the nature of the changes producing development is such that the record of each previous condition is successively and entirely obliterated ; so that the science of embryology is possible only by direct observation of each successive stage. If this were true also of the earth, a history of the earth would, of course, be impossible. But, fortunately, we find that each previous condition of the earth has left its record indelibly impressed on its structure.

 

Elements of Geology, pg. 2, Joseph LeConte, D. Appleton and Company, 1896

 

Namely, LeConte emphasizes that the central tenet of the organic sciences (biology) is the understanding of physiology through the lenses of anatomy and embryology. Conversely, he states that the central tenet of geology is historical geology (the organic equivalent being embryology), and that the history of the earth can only be studied through the lenses of structural and dynamical geology. Interestingly, LeConte alludes here to a principal that might have been known at the time, but the specific mechanism largely a mystery – that biological organisms selectively kill of cells and tissue during various stages of embryonic development, or even post-embryonic, through specific biochemical pathways that have evolved to activate at specific times during an organisms life cycle. In this way, LeConte is correct – biology tends to eliminate its past completely through selective pruning, whereas geology has no pruning mechanism (save, perhaps, volcanic processes). In other words, in LeConte’s view, geological processes tend to preserve more historical information than organic ones.

Furthermore, another interesting faucet of science is touched on in this passage. Famously, Ernst Haeckel wrongly concluded from his embryological observations that “Ontology recapitulates phylogeny”. That is, the entire evolutionary history of an organism is played out during the embryological development of an organism (e.g., from fish to vertebrate in the development of a human fetus). This was later shown to be an incorrect conclusion as it was shown that developmental processes only retain traits or phases as they are relevant to the evolutionary fitness of an organism, and so the presence or absence of developmental phases (e.g., a “fish” phase or a “tail” phase) during embryological development reflects the steps needed to produce a healthy, functioning organism rather than specifically retaining each step of organism’s evolution in development. That is to say, entire phases of embryological development might be lost or gained regardless of evolutionary history.

Part of the thinking that led to the widespread belief that “Ontology recapitulated phylogeny” went in line with the tendency for early scientific thinkers to occasionally, or frequently, embrace teleological thinking – the process of describing scientific processes in terms of their apparent goal – which led to the anthropomorphical description of many processes later shown to be undirected (e.g., Darwinian selection and dynamical geological processes). Interestingly, LeConte’s statement that organic processes obliterate information, seems to directly contradict the idea that evolutionary history reflected during embryonic development, making him a possible early-adopter of the more rigorous Darwinian lines of thinking regarding the type of information that embryonic development actually portrays.

In concluding his introduction, LeConte describes the prime objective of geology “as the history of the earth and its inhabitants, as revealed in its structure, and as interpreted by causes still in operation”. This is an interesting “prime objective” of geology and it might find itself at odds with modern interpretations of the geological sciences. Although the study of the history of broad patterns in life and macroevolution are still relegated to geology in that tend to pertain to the major geological epoch’s described in earth’s history, the majority of specific scientific understandings for the “inhabitants” of earth have shifted into their own sciences: paleontology (the study of extinct organisms) and neontology (the study of extant, still living organisms). In this sense, modern students of geology may be confused by LeConte’s introduction and find it strange to learn that they are about to have indepth discussions regarding the evolutionary history of life on earth, but LeConte might respond that the two budding sciences are still deeply intertwined and so should be studied together.

Next up will be LeConte’s introduction to Dynamical Geology – the science of the active processes of geology as they can be observed in modern times. Stay tuned!

How to “Science” When Theories are Un-Testable

Modern science has reached an interesting conundrum – top fields in theoretical physics and evolutionary biology often seem untestable. That is to say, scientists lack methods for generating empirical data to answer real questions in science. How do we cope with this when funding decisions often require the incorporation of real data into proposals? The answer is that scientists are continuing their research in the form of logical thought experiments – arguments that are logically valid, but usually end arriving at unrealistic scenarios that are either too expensive or too impractical to garner scientific funding. While it seems like this might be a negative direction to move scientific research into, it is actually very important. Allowing science to exist in a more free-form pattern, unrestricted in some cases (e.g., string theory) by the requirement of empirical data, might allow for scientists to make the inevitable logical “leap” into methods for generating that empirical data. In other words, thinking philosophically about science allows scientists to test the logically validity of their ideas before even beginning the design phases of experiments.

Cosmic Microwave Background (CMB) radiation.

Cosmic Microwave Background (CMB) radiation. ESA and the Planck Collaboration.

One of the most important fields of science where this is occurring is theoretical physics. Recently, scientists have begun to incorporate ideas regarding multiverse theories into standard physics problems, albeit with negative reactions outside of the scientific community. String theory, for example, has been called all myriad of terrible things, and yet remains at the forefront of theoretical physics research. What does this mean for the advancement of the science? Well, on the one hand, it’s a great example of where a scientific field can proceed to generate major breakthroughs in mathematically methodology, it’s also an example of where the over emphasis of a single methodology can drown out other equally plausible ideas. In other words, in a scientific field where no empirical data exists, scientists tend to throw their hand in with the most accepted “non-empirical” method instead of investigating other non-empirical methods equally. This highlights the need for a broader discussion on how scientists should approach problems that do not yield empirical data.

Evolutionary biology is another great example. Popular science and non-scientists harshly criticize theoretical evolutionary biology as lacking empirical data much the same way as string theory is criticized. And so we arrive at a point where scientists know that something is intuitively correct (that evolution occurs), and logically correct (we have data to support evolution occurs), evolution is not a process that is directly observable or measurable in the same way that temperature and electrical charge are measurable. One of the ways that scientists get around this problem is the development of measurable metrics that reflect what we intuitively think of as an evolutionary process (e.g., Hardy-Weinberg Equilibrium). And so the field of evolutionary biology is largely able to generate empirical data using these metrics, whereas theoretical physics is still unable to create measurable metrics to generate empirical data reflecting the predictions of string theory.

This is where I believe the downfall of physics is the hesitation of scientists to accept plausible metrics that intuitively reflect what scientists want to measure. A major step forward in this thinking was made by Ranga-Ram Chary of the Planck Institute in 2015 when he suggested that perturbations in the cosmic background microwave radiation are indeed a way to measure and test multiverse theories. But does this idea stand up to other forms of scientific rigor, that is, the principle of falsifiability? Perhaps not, since there are more than one other possibility for the perturbations we see in the background radiation. However, in my opinion, this is a great step forward in the type of thinking that we need to employ to dig out of the theoretical hole of string theory. The acceptance and subsequent debate of intuitive ideas like this might lead to the development of more rigorous, falsifiable, metrics that relate to the predictions of the string theory and an important step forward in the modern application of the scientific method.

Blood quantum and DNA testing in Native American tribes

Originally written April, 2012, by Bryan White

The issue of what determines whether or not a person is an official member of a Native American tribe constantly changes and evolves with society, culture, and technology. In the New York Times article “Ancestry in a Drop of Blood”, Karen Kaplan traces the struggle of Marilyn Vann, a black woman that considers herself Native American. It had always been a dream of Marilyn’s to identify with her Native American ancestry, which she had known through many paper documents to be true, in an official way by joining the Cherokee Nation. The Cherokee Nation is one of the largest federally recognized tribes with over 299 thousand members enrolled, over 63% of which live in Oklahoma. While I agree that official membership to federally recognized tribes should be restricted, but the basis for those restrictions should not be made on centuries old documents such as the 1907 tribal roll call the “Final Rolls of Citizens and Freedmen of the Five Civilized Tribes in Indian Territory (Dawes)”.

The existence of federally recognized tribes is important both for Native American culture as well as American and Human culture as a whole. Each tribe has a multitude of unique cultural characteristics that are worth preserving in of themselves, and allowing members of these tribes federal recognition helps to preserve and ensure that each of their different cultures are protected in the way that actual members of that culture feel are proper. For this reason I agree it is important to maintain the cultural integrity of the tribes, so that each member of the tribe has some investment in protecting that culture. Tribal membership, the process of becoming a member of a federally recognized tribe, should therefore enact some requirements that ensure each member both has some investment in protecting the tribal integrity, and also deserves some benefit or reparations for the past suffering of their people. Marilyn Vann felt that she had enough connection with her Cherokee ancestry that wished to join the tribe official, and may have perhaps contributed to its cultural growth and preservation. However, the means by which that integrity is ensured can give rise to many legal and ethical problems, as is demonstrated in the fact that Marilyn Vann was denied her membership to the Cherokee tribe.

One such basis for a person gaining tribal membership is that of blood quantum, or the amount of “Native American blood” that a person has. However, the methods in which “blood quantum” is determined, and indeed the very definition of what “blood quantum” is, are somewhat tenuous and dubious. For example, under one definition, if a person has even a single drop of Native American blood, that person is considered Native American. However, under another definition, a person must have at least 25% Native American “blood” to be considered an actual Native American. The irony is that this method is the same one purveyed by proponents of racism during a segregated America, and is still widely used by the Federal Government to enforce the idea of race for employees and students. According to this rule, Marilyn Vann could not be determined to have enough Native American blood because her father had been listed as a Freedmen (a former slave) rather than a Cherokee, despite her knowledge that she was indeed part Cherokee.

One alternative method for determining ones claim to have Native American ancestry is to use DNA testing in which a potential tribe member. Marilyn Vann sought this method because she wished to be validated in her belief that she was indeed part Cherokee, even though her skin color and facial features probably looked more African American. The process of DNA testing to determine ones geographic ancestry is carried out by taking a sample of a person’s DNA and comparing several genes to a database wherein genetic sequences are already matched to their geographic location. According to this test, Marilyn Vann found out that she was indeed at least 3% Native American.

Should Marilyn Vann then be admitted to the Cherokee Nation? Personally, I believe the cumulative evidence suggests that Marilyn Vann should be considered a full member of the Cherokee Nation because she has taken the time to compile actual paper evidence of her ancestry, as well as genetic evidence. That time and effort suggests that Marilyn is interested in becoming an official member of the Cherokee Nation under goodwill, and that her intentions are to maintain the integrity of the tribe, and gain a sense of her position in the world as an African American and Native American. If, for example, Marilyn had simply taken a genetic test and found out that she was some small part Native American, then I would question her motives in becoming an official member of the tribe, but this is not the case. Hopefully tribes will begin to integrate the use of DNA testing in a fair way so that people who consider themselves Native Americans will not be shunned of their ancestry because of old and outdated methods that are based on the precepts of racism.

Europa and Ceres – Two Inter-Solar-System Bodies that May Contain Oceans of Liquid Water

Europa

Europa, one of Jupiter’s largest moons, is considered to be one of the most likely places within the solar system that might harbor life. Europa possesses a great number of characteristics that might lend themselves to the independent evolution of life, similar to what occurred on Earth. In this essay, I will outline some of those key characteristics and highlight where and why they might suggest Europa is a potential breeding ground for, at the very least, microbial organisms undergoing Darwinian selection.

Layers of Europa's Crust.

Layers of Europa’s Crust. Public Domain by Latitude0116 and RP88. Wikimedia Commons.

One of the primary characteristics of Europa that suggest it might harbor life is the presence of a water-ice crust (that is, instead of a rocky crust like on Earth, Europa has a crust made up of frozen water-ice). The presence of frozen water-ice in of itself, however, is not a major astrobiological finding. More importantly, beneath the water-ice crust of Europa, it is hypothesized that a liquid ocean of water exists, warmed from a likely volcanically active iron-nickel core. This liquid ocean is most likely trapped between a rocky nickel-iron mantle and frozen water-ice crust, forming a bubble where temperatures are warm enough to allow liquid water to exist, with the help of high levels of salts. Evidence for a liquid ocean beneath the frozen crust has been identified by the Hubble Space Telescope in the form of liquid vapor jets (cryogeysers) erupting from the surface of Europa. This suggests that the ocean is under pressure, most likely created by the thermal heat generated by Europa’s core, and rocky ice layers, causing increased pressure on the liquid ocean trapped between two rocky layers.

Heat is most likely generated in the core and rocky layers due to tidal flexing, that is, the gravitational pull of Jupiter causes deformation in the metallic core and rocky ice sheets. This deformation is the result of bending, crystalline structures – the act of which generates heat. This heat is most likely enough to allow the liquid ocean layer to persist beneath the rocky crust.

The composition of Europa’s surface is hypothesized to contain a high level of dissolved “sea salt” (sodium chloride), which would contribute to maintaining its liquid form at low temperatures and present an oceanic environment similar to that on Earth’s. However, because the concentration of sea salt is so theorized to be so high on Europa’s ocean, only extreme halophilic bacteria-like organisms could survive such conditions. With a subsurface temperature of -171 degrees Celsius, and a salt concentration significantly higher than Earth’s ocean, this seems like a plausible conclusion. However, this leaves open the possibility that pockets of warmer water, or haloclines (areas of lesser or greater salt concentrations), that may provide environments for more complex life forms to exist.

The search for evidence of life on Europa continues with NASA’s Europa Multiple-Flyby Mission (http://solarsystem.nasa.gov/missions/europaflyby) which will conduct multiple, low-angle flybys of Jupiter’s moon Europa. Interestingly, the EMFM probe will posses an ice-penetrating radar, which should allow for scientists to take a closer look beneath the surface. Unfortunately we would not see the results from this mission until, at the earliest, 2026. Until then we will have to rely on near-earth telescope data and the image data that other probe missions have produced.”

Ceres

Ceres, unlike Europa, is not a moon – it is a dwarf planet. Interestingly, it is the only dwarf planet that makes its home within the inner solar system. Specifically, Ceres orbits around the sun among the other asteroids and comets within the Kuiper Belt. Similar to Europa, however, Ceres sports a multi-layered crust that houses a large body of frozen water-ice. Unfortunately, it is not currently known whether or not any of the water on Ceres is still liquid. However, Ceres poses an interesting conundrum for astrobiology. Since it is a member of the inner solar system, it stands as one of the possible originating points for life in the solar system. How could life have evolved on this cold, icy, rock that is similar in size and shape to Pluto? Well, most likely, due to Ceres’ small size, it would have cooled and formed a proto-planetary disc much earlier than the Earth (4.5 billion years ago). If Ceres cooled enough to have a stable atmosphere (albeit a small one due to its small gravity), then the organic chemical reactions needed to produce complex nucleic acids, proteins, and lipid structures may have begun much earlier than they would have had on Earth.

Ceres Structural Layers.

Ceres Structural Layers. Public Domain by NASA/JPL. Wikimedia Commons.

The next step would have been for some asteroid or comet to impact with Ceres and drag along any proto-bacteria type life forms with it, all the way to Earth. According to this hypothesis, Ceres would have been the “founder” of life in the solar system, giving rise to the earliest forms of bacteria that populated an early Earth. Of course, conditions on Ceres would not have remained favorable to life for very long (in geological time), so any life forms that did evolve on Ceres would not have likely evolved much further than a simple bacteria. In that sense, Ceres might be a good place look for early signs of bacterial life, but we shouldn’t expect to find much more than that.