Darwin in Context

I've been trying to figure out what to write about for my Blog for Darwin entry. I've been reading Origin, but I haven't finished it yet (the last few chapters are not nearly as interesting as the first few). Even so, as I've been reading, I haven't really been struck with any brilliant insights or profound thoughts. One thing that has occurred to me a lot, however, is just how much we've learned since Darwin's time. So, I thought that for my BfD contribution, I would outline what was going on in science while Darwin was doing his thing. I'm hoping it might give some insight into what Darwin did and didn't know, and how his ideas may have been influenced by what was going on around him.

Disclaimer: I am not a historian; the summary below is not intended to be exhaustive. I'm mainly going to focus on the big ideas and events; if you're interested in the gory details, there are a plethora of excellent books out there to satisfy you, I'm sure. Also, please note that I've done my best to verify all of the information below, but I'm not an expert in this stuff. Any errors are solely my responsibility. If you find any, please let me know!

Chemistry
By the 1800s, the study of chemistry was becoming modernized. In the 1600s and 1700s, naturalists began to discover general laws that govern natural processes. Both Boyle's law and Charles's law (on the properties of gases) had been discovered by the early 1800s; a number of gaseous elements and compounds (including oxygen, nitrogen, and nitrous oxide) had been isolated and described.

John Dalton proposed his atomic theory in the early 1800s; although his concept of the atom (i.e., hard, solid, indivisible sphere) has since been replaced, his work on the conservation of mass and the law of definite proportions still underlies much of modern chemistry. His law describing the partial pressures of gases in a mixture is still used today.

The early 1800s also saw the publication of Avogadro's hypothesis (i.e., that equal volumes of gases at the same temperature and pressure contain the same number of molecules).

In the mid 1800s, Lord Kelvin proposed the idea of absolute zero and an absolute temperature scale.

What Darwin didn't know: Most elements were not identified or isolated until after the 1860s. Electrons were not discovered until the late 1800s; the concept of the atom as we know it today (i.e., nucleus of protons and neutrons surrounded by electrons) was not developed until the twentieth century. The nature of chemical bonding was also unknown in Darwin's time, as was the periodic table and the notion of periodic properties.

Physics
Electricity and magnetism were the order of the day in eighteenth and early nineteenth century physics. Franklin "discovered" electricity in the late 1700s; Ohm's law was proposed in the 1820s; Oersted discovered evidence of a magnetic field around a current-carrying wire in 1820; Faraday discovered electromagnetic induction in the 1830s; Joule and Helmholtz proposed the law of conservation of energy in the 1840s.

Newtonian mechanics were well established by the 1800s.

What Darwin didn't know: Radioactivity, quantum physics, relativity, and nuclear physics were decades to centuries away in Darwin's time.

Biology
As Origin does a pretty decent job of summarizing what was going on in evolutionary biology (such as it was) at the time it was written, I won't spend space on that here. In the mid-1800s, the idea that all living things are made of cells was just beginning to take hold; spontaneous generation was beginning to be discredited. Taxonomy was becoming more rigorous. Paleontology was starting to become a well-established field; most naturalists accepted that the majority of the fossils being unearthed around the world represented organisms that no longer exist.

What Darwin didn't know: Genetics and the theories of inheritance had not been discovered when Darwin did his work; a story I've heard (which I have not verified) is that Darwin had Mendel's papers on his desk when he died. Molecular biology, most of microbiology, and, of course, genomics were completely unknown. The germ theory was still a few years off, as was the discovery of many disease-causing microorganisms.

Earth Science
Naturalists were just beginning to come to grips with Earth's immense age during the late 1700s and early 1800s. The best consensus was that Earth was a few hundred million years old at most; these estimates were based on rates of physical processes (such as sedimentation and cooling). Radioactivity was unknown, so both a method for accurate dating and a mechanism for keeping Earth "warm" for long periods of time were lacking.

However, the principle of uniformitarianism was pretty well accepted, having been proposed in the late 1700s. As I mentioned above, paleontology was becoming more rigorous and "scientific," although some of the interpretations of fossils--especially dinosaurs--were rather interesting.

The idea of a global geologic column or time scale was becoming increasingly popular. Indeed, Darwin makes many references to the accepted contemporary time scale (although the time scale of the mid-nineteenth century bears little resemblance to our modern one).

What Darwin didn't know: The theory of plate tectonics was still about a century away. Radiometric dating (and an understanding of how radioactive decay has heated the planet) wouldn't be developed for quite a while, so Earth's true age was unknown to Darwin. In addition, research into the fossils and strata of the planet was generally restricted to Europe and North America, so Darwin's (and everyone else's) ideas about geologic history (and paleontology) were accordingly limited.

Well, there you have it: the two-bit tour of the state of science in the 1860s. I hope this is helpful to someone. If I had time, I'd go into more detail...yet another item to add to my "things to do when I win the lottery" list!

Blogging for Darwin

I joined the Blog for Darwin blog swarm (which means I have to actually finish Origin soon, so I have something to write about). Check it out--it's pretty cool.

I haven't decided yet what to write about; I'm having a hard time coming up with anything super profound. I'll wait and see if any inspiration strikes as I keep reading.

Thanks to Newton's Ocean for the link.

You would think...

...that in 200 years, the anti-science crowd would have come up with some new objections to evolution. Apparently not: Check out this quote from Origin.

Long before the reader has arrived at this part of my work, a crowd of difficulties will have occurred to him...These difficulties and objections may be classed under the following heads:--First, why, if species have descended from other species by fine gradations, do we not everywhere see innumerable transitional forms?...

Secondly, is it possible that an animal having, for instance, the structure and habits of a bat, could have been formed by the modification of some other animal with widely-different habits and structure? Can we believe that natural selection could produce, on the one hand, an organ of trifling importance, such as the tail of a giraffe...and, on the other hand, an organ so wonderful as the eye?

Thirdly, can instincts be acquired and modified through natural selection? What shall we say to the instinct which leads the bee to make cells, and which has practically anticipated the discoveries of profound mathematicians?

These questions, of course, have many parallels in the standard litany of "problems" with the theory of evolution often spouted by creationists and intelligent design proponents. Is this yet another example of Darwin's apparent prescience? Or is it more accurate to say that Darwin's statements echo those of modern-day denialists because they are building on the "work" of those who came before, who undoubtedly read Darwin? If the latter, it's really a shame they didn't read the whole book. Even if they'd read a few pages further on, they would have come across this beauty:

When it was first said that the sun stood still and the world turned round, the common sense of mankind declared the doctrine false; but the old saying of Vox populi, vox Dei, as every philosopher knows, cannot be trusted in science.

Perhaps it might be better said that Vox populi, vox veritas "cannot be trusted in science." But the sentiment still holds: Just because most people think it's so, doesn't make it so. The fact that so many people argue that we should teach the Bible as science because "most Americans believe in God" speaks to a fundamental lack of understanding of the way science is done. But I'm not the first to make that statement, nor will I be the last.

More Darwin progress

Well, I've made it through chapter 3. Here are my impressions so far:

First, I'm really impressed with Darwin's writing. I wish modern research results were presented in as readable and understandable a way. Yes, he's using rather flowery Victorian prose, and he tends to overuse the semicolon and the hyphen--but then, there are a lot of people who do that today, and some of them run the government. And at least he's managed to refrain from quoting anything in French (or, worse, German...) since the "Historical Sketch." And at least he doesn't capitalize random words.

Second, I've been very interested to see exactly how much Darwin didn't know--and, given how much he didn't know, how much he got right. It's mind-boggling to think that he managed to get the main ideas right when he didn't even know about genes. (A friend of mine recently told me that they found a copy of Mendel's paper on Darwin's desk after he died--apparently, he just didn't get around to reading it. Imagine what he might have done with Origin if he had!)

On his blog, John mentions that he scribbled in the margins of his book the modern terms for the concepts Darwin presented in chapter 3. I have to admit, I was tempted to do the same thing in my copy (although the thought occurred to me back in chapter 1). I find it fascinating that many of the ideas that Darwin apparently had to defend are taught in high-school biology today. For example, consider this, from chapter 1:

Indefinite variability...has probably played a more important part in the formation of our domestic races. We see indefinite variability in the endless slight peculiarities which distinguish the individuals of the same species, and which cannot be accounted for by inheritance from either parent or from some more remote ancestor.

Mutations, anyone?

John points out several other examples from ecology.

I was also reassured to learn that the debate about what constitutes a species has been going on since before Darwin. I was tempted to think that it was the offspring of the digital age--i.e., the need of modern scientists to cut into chunks things that are naturally continuous.

More to come...

Darwin progress

I started On the Origin of Species last night. I'm reading a slightly different version than John is--he's reading the first edition, and I'm reading the 6th (which, according to the book jacket, is the last edition to have had edits made to it by Darwin himself). However, the introductions are apparently sufficiently similar that I can understand his discussion of the introduction. (Plus, I have to admit that I'm glad he didn't get through chapter 1 last night, either. One of the problems with doing most of my reading in bed is that I periodically fall asleep before I've finished.)

At the end of his post, John mentions his surprise that Darwin acknowledges his and Wallace's nearly simultaneous arrival at the concept of natural selection. That didn't surprise me very much, because the preface to the 6th edition consists of an "Historical Sketch of the progress of opinion on the Origin of Species, previously to the publication of the first edition of this work." In it, Darwin summarizes the work of various key players in the study of the origin of species. The first person he discusses in any depth is Lamarck (although he gives passing reference to Aristotle, as well), and his summary extends to publications and presentations by Huxley and Hooker in late 1859, the same year the first edition of Origin was published.

I found the historical sketch to be quite an interesting read (despite his penchant for quoting works by French authors in the original language). Although it pains me to admit it, my knowledge of the history of the theory of evolution is abysmally lacking. I was surprised at the sheer number of researchers that had done significant work (and reached conclusions in line with, if not completely similar to, Darwin's) prior to the publication of Origin. Of course, I know that Darwin held off publication of the book for a while after formulating his ideas. But I do find it refreshing that he acknowledges the influence of others on the generation of his ideas.

Another line in the introduction that I found interesting: "No one can feel more sensible than I do of the necessity of hereafter publishing in detail all the facts, with references, on which my conclusions have been grounded...For I am well aware that scarcely a single point is discussed in this volume on which facts cannot be adduced, often apparently leading to conclusions directly opposite to those at which I have arrived." (p. 2)

I was struck by the apparent prescience of this statement: could Darwin, perhaps, have been anticipating the likes of Ray Comfort?

Blogging Darwin

John Whitfield is embarking on a quest: He's going to read On the Origin of Species by Darwin's birthday (Feb. 12). Not only that, but he's blogging about it.

Having just picked up a copy at my local half-priced bookstore--and despite being in the middle of three other books--I think I'm going to try to follow along. I can't guarantee that I'll respond to every chapter, but as I've never actually read it, I figure now's as good a time as any. If nothing else, by the end I'll at least be able to counter quote-mining creationists with "Have you actually read the book?" and not be hypocritical.