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March 14, 2009: Just a Theory

This entry is continuation of the last one. It was getting a bit too long but I want to deal with another aspect of it. One of these days I am going to organize these into a proper blog so that people can leave comments, but first I have to get WordPress running on my server.

Last Darwin Day (Feb. 12) the creationists at my school had a booth set up and I spent some time chatting with them. Typical of creationists, they were profoundly ignorant of real science but firmly believed in their standard creationist talking points, one of which is that the laws of thermodynamics would make evolution impossible. I addressed this below, but I want to expand on a claim made by the woman I was talking to, that “Laws” are called laws because they are absolutes that are never violated, while a theory is always tentative.

To briefly repeat what I said before, a theory can contain laws, but a theory can never become a law. A law is a short statement of a specific principle, while a theory is a comprehensive description of a class of phenomena. Think of it this way: A law will fit on a t-shirt, but a theory fills up books.

As to the claim that laws are absolutely inviolable, let’s consider thermodynamics again. Thermodynamics describes the aggregate behavior of a very, very large number of particles (atoms or molecules). For example, just 12 grams of carbon contains Avogadro’s Number of atoms, 6.022 × 10²³. Thermodynamics is essentially statistical in nature, but because the number of particles is so large, their behavior is quite predictable. This is predicted by statistics.

The Law of Large Numbers states that the more events you have, the closer their average behavior will be to the most probable outcome. As an example, suppose you are flipping a coin. The statistical odds for any flip are exactly even: heads or tails. If you just flip one coin, you cannot predict the outcome at all. If you flip ten coins, you will get five heads and five tails more often than the other possible combinations, but they will still show up often, and so you probably won’t get exactly half heads and half tails. However, if you flip a million coins you can very confidently predict that you will get 50% heads and 50% tails, with extremely high precision. Also, your arm will be very tired.

Because we typically deal with amounts of matter that contain an unimaginable huge number of particles, we always see the most probable behavior. But if we had a system that only contained a few molecules of gas, we would see most of the laws of thermodynamics being violated. The First Law, conservation of energy, would still hold, but the Second Law (the entropy thing) would fail regularly, as would Boyle’s Law, Charles’s Law, and the Ideal Gas Law. Of course, in this case it doesn’t even make sense to define thermodynamic properties such as temperature and pressure, as they are statistical averages themselves and only make sense with a large number of particles.

The point here is that “Laws” are not inviolable. In fact, many of our scientific “laws” are just approximations. The Ideal Gas Law, for example, describes something that doe not exist in nature (that’s the “ideal” part). It is, however, a pretty good approximation for many real gases. So why do we call it a law when it is not always right? Becaause it fits on a T-shirt!

February 26, 2009

Bryan Fischer is a former pastor of a local church, who is now the Executive Director of the Idaho Values Alliance, an organization primarily devoted to getting Pastor Fischer’s name in the news while he repeats the standard evangelical right-wing talking points (Liberals are bad, sex is bad, gays are bad—these guys think about sex a lot). Pastor Fischer may be an authority on the Bible, but unfortunately he seems to think that his expertise also extends to science.

I was poking around the IVA website when I found a position paper called Defeating Darwin in 4 Easy Steps. Now evolution is outside of my field, but I’ve been reading quite a bit about it ever since I realized that the evolution deniers were saying things about physics, astronomy, and geology that were bunk, and they were trying to get schools to teach nonsense in place of science.

Fischer’s paper is an incredible amalgamation of scientific misunderstanding and outright falsehoods. His introduction contains a bizarre statement about how random collisions of atoms could not produce thoughts, but that is just too weird to comment on, so let’s have a look at his 4 easy steps.

1. The First Law of Thermodynamics

The first of his four steps is the First Law of Thermodynamics, of which he says

This law (note: not a theory but a scientific law) teaches us that matter and energy can neither be created nor destroyed.

First, he displays the common confusion that a law is somehow superior to a mere theory. Wrong. A theory can contain laws, but a theory can never become a law. A law is a short statement of a specific principle, while a theory is a comprehensive description of a class of phenomena. Think of it this way: A law will fit on a t-shirt, but a theory fills up books.

I get particularly annoyed when evolution deniers bring up the Laws of Thermodynamics, because I know something about thermodynamics, having sat through a couple of courses in graduate school. I don’t know what they cover in Bible College, and I don’t really want to, but I’m betting there’s not much physics.

The Laws of Thermodynamics are not even strictly 100% correct. They are statistical constructs that describe the average behavior of large numbers of particles (the second law in particular), and they were written in the 1800s before we knew anything about relativity or quantum physics, both of which require some modification of the laws. For example, relativity tells us that matter can indeed be created and destroyed according to the famous E=mc² formula, and furthmore, quantum physics allows particles to appear out of empty space for absolutely no damn reason, subject to restrictions on their lifetimes (see Virtual Particles).

Fischer’s point in bringing up the first law is to suggest that the matter and energy in the universe could not have appeared from nothing, thereby refuting the Big Bang theory. What this has to do with evolution is beyond me. Evolution is about the development of life on Earth, while the Big Bang is about the development of the Universe. I don’t think evolutionary biologists use much cosmology in their work. Nevertheless, he has stepped right onto my turf, so I’m going to address this point in spite of its irrelevancy.

The matter and/or energy in the Universe didn’t have to appear from nothing, but the reason is a little bit hard to picture. There are some other explanations from quantum physics and multi-dimensional string theory, but I like this particular one. You see, there was no time “before” the Big Bang. Relativity tells us that spacetime is curved in such a way that time itself began at the Big Bang. To talk about a time before the Big Bang is as meaningless as asking what is north of the North Pole, and for the same geometric reason (only it’s in 4 dimensions, which you really can’t picture without mind-altering chemicals). If you are standing at the North Pole there is no such direction as “north”, and at the beginning of the universe there was no such time as “the past.” Therefore the matter in the Universe has existed for all time, even though the Universe has a finite age. Another way to look at it is that the laws of physics began with the Big Bang, so the matter/energy was already there. There are of course many questions one can ask about the hows and whys of the Big Bang, most of which we can’t answer, but the First Law of Thermodynamics isn’t one of them.

2. The Second Law of Thermodynamics

This is a favorite of evolution deniers, mainly because they don’t know what it really says. It takes a bit of math to properly define it, so we tend to give out a layman’s version of it that says something like “Closed systems always change in the direction of increasing disorder,” which the evolution deniers then take to mean that evolution is impossible because life represents an increase in order. Part of the problem here is defining “order” or “disorder.” We use a quantity called entropy, which has a very strict mathematical definition but nevertheless represents something much like “disorder.” The problem that evolution deniers always miss is that the Second Law applies to the whole system, not just one part. It’s OK if entropy decreases in one place, as long as it is increasing somewhere else. Like the Sun.

3. Fossils

Biology is not my field, but I am fairly well read. Pastor Fischer is apparently not. He drops the ball with his very first sentence:

Realize that the fossil record is the only tangible, physical evidence for the theory of evolution that exists. The fossil record is it. There is absolutely nothing else Darwinians have they can show you.

The truth is that the theory of evolution would still be well supported even if we didn’t have a single fossil. Comparing different existing species is what led Darwin to his theory, and evolution is still the only explanation for the similarities and geographic distribution of life on Earth. We also have another tool today that Darwin did not: genetics. Without evolution it would be utterly impossible to explain what we see when we examine DNA.

Then he gives us this gem:

But, sadly for Darwinians, after 150 years of digging in dirt all around the world, there are still no transitional fossils at all, not one!

Umm...

What transition do you want? How about fish to land animals:

How about land animals back to fish (whales, to be precise):

And of course the one that really gets their panties in a bunch:

Tell my, Bryan, where is the line between apes and humans? There isn’t one—humans are apes.

He then touches on punctuated equilibrium, quote-mining Stephen Jay Gould to make it seem as though Gould did not believe that any transitional fossils existed. This creationist claim has been dealt with by others, so I will skip that and go on to his next blunder:

What the fossil record teaches us, in contrast to the theory of evolution, is that increasingly complex life forms appear fully formed in the fossil record, just as if they were put there by a Creator. This is especially true of what is called the “Pre-Cambrian Explosion,” the vast, overwhelming, and quite sudden appearance of complex life forms at the dawn of time. Evolutionists are at a total loss to explain the Pre-Cambrian Explosion.

First of all, it’s called the Cambrian Explosion, and it was hardly at the “dawn of time”. It was 530 million years ago (the Earth is 4.5 billion years old, and the Universe is about 13.7 billion years old). The “sudden appearance” took place over a period of 70 to 80 million years. The fossil record troubled Darwin because at the time there were no known Precambrian fossils (maybe they all exploded!). Well, now there are. Scientists haven’t been just sitting on their butts for the last 150 years, and they are not exactly “at a total loss” to explain the Cambrian Explosion.

4. Genes

I can’t pretend to be an expert here, but a couple of blatant lies are easy to spot.

The only mechanism – don’t miss this – the only mechanism evolutionists have to explain the development of increasingly complex life forms is genetic mutation.

Sorry, no. Genetic mutation is really important to evolution, but so are other things like genetic drift or endogenous retroviruses, which insert themselves into DNA and if it happens to be a germ cell (a sperm or an egg) then that new DNA is passed on. They make up 8% of human DNA.

But the real whopper is this one:

The problem: naturally occurring genetic mutations are invariably harmful if not fatal to the organism. Rather than improve an organism’s capacity to survive, they invariably weaken it. That’s why the phrase we most often use to refer to genetic mutations is “birth defects.”

Completely wrong again, Bryan. The overwhelming majority of mutations have no effect whatsoever. In fact, humans have an average of 175 mutations per generation. That's just going from your parents to you.

Fischer then quote-mines some guys I've never heard of to suggest that there have never been any observed speciation events. That is completely false.

Someone needs to tell this guy about Wikipedia. It would seem that fact-checking is not a Christian Value. Either that or telling the truth isn’t a Christian Value. I’ve seen this behavior in other creationists--there is something that has gone astray in their thinking skills, and it leads them to a state of absolute certainty that they are right, without the need to check their facts. Why bother checking when you know that you are right? Fortunately, scientists can’t and don’t think this way. If they did, other scientists would rip them to shreds. Scientists have to follow the evidence, wherever it leads. That's all there is to it.

February 12, 2009

Thursday, February 12, 2009 is the 200th anniversary of the birth of two very influential people, Abraham Lincoln and Charles Darwin. Coincidentally, this year (although not this exact day) is also the 150th anniversary of the publication of Darwin’s Origin of Species, in which he describes his groundbreaking theory of evolution by natural selection. Although I’m not a biologist, we science types are all in the same business and I thought it appropriate to give some props to Big Chuck.

A few weeks ago, on January 24, the journal New Scientist published an issue with an overly sensational and much criticized cover proclaiming that “Darwin Was Wrong!” Specifically, the cover story was about how we no longer use Darwin’s model of the “tree of life.” It turns out that life is considerably more complicated than Darwin ever guessed, and the links between species form more of a bramble than a tree. While that’s interesting, it’s hardly surprising that science has learned a few more things over the past 150 years.

Of course Darwin was wrong about some things. So was Newton. So was Einstein. There has never been a human being who was always right (well, except for my ex-wife). What’s important is not what he got wrong but what he got right, and that idea, natural selection, is still to this day the guiding principle of biology. Just as Newton laid the foundations of physics, Darwin gave biologists a theory that for the first time allowed them to explain what they were seeing. Before Darwin, biology was largely a matter of collecting and classifying. While that work was and still is important, science strives to answer the hows and whys. This is what Darwin’s theory does.

Non-scientists often don’t understand the difference between a scientific theory and an idea or a hypothesis. The idea of evolution was not Darwin’s. Even before he was born there was speculation that different species descended from a common ancestor, but that idea alone is not a theory. What Darwin provided was an explanation for how that could happen, and that is the “theory” of evolution. Darwin’s theory wasn’t the only one or even the first one, but it was the right one. It wasn’t even the only right one, because the naturalist Alfred Wallace independently arrived at much the same conclusions. But Darwin did it first. Few scientists have had such lasting impact on their field, so raise a glass today to this great man of science.

December 24, 2008

I've been meaning to put this up. Now I'm on vacation in sunny Arizona, so I found the time. Feel free to respond.

Notes

When?  The timeline of life is straight from Wikipedia. Of course there is some uncertainty to it, as there is in all science, but the general outline is uncontroversial. The ID proponents, on the other hand, refuse to speculate on when the supposed intelligent intervention took place. The reason they do this is political. The ID movement includes young-earth creationists (biblical literalists who believe the world was created in six days less than ten thousand years ago) as well as those who accept the billions of years claimed by science but still have a need for divine intervention along the way.  The ID proponents obviously cannot discuss timelines without alienating some of their supporters, so the subject is taboo.  It does seem a little odd, though, to be discussing history without speculating on when it happened.

How?  The ID movement is also completely silent on the details of how the designer effected his/her/its design. Were the components of DNA molecules moved about by a force previously unknown to science? Is this process still occurring, so that we might observe it? Or was it just magic? Or…God? Of course the ID movement is very careful not to admit the truth of their religious motivation, because that would present a constitutional barrier to teaching it in public schools. Hence, it is better to just not say anything at all.

Testable? Predictive Power? Falsifiable?  These three are all sides of the same coin, if you could have a 3-sided coin.  Evolution makes predictions which are testable. The science journals are filled with thousands of such studies, and none have raised any doubts about the general principles of evolution (although the details are of course always being fine-tuned).  Evolution can predict what sorts of fossils will be found in a particular rock layer, or scientists in the laboratory can perform experiments with rapidly reproducing organisms such as yeast cells or the ubiquitous fruit fly. We are still waiting for testable predictions from Intelligent Design.

As for falsifiability, the biologist J. B. S. Haldane famously suggested that a Precambrian rabbit fossil would disprove evolution. Needless to say, we still haven’t found a Precambrian rabbit fossil. But how can you disprove a theory that allows magic to occur? A scientific theory must explain not only why things are the way they are, but also why they are not the way they aren’t. Unfortunately, allowing supernatural intervention explains anything and everything, and therefore leaves us with no way to distinguish what is possible from what is not.

December 19, 2008

IRISH YOGA

December 15, 2008

November 30, 2008: Cosmology

The universe is really 4-dimensional (at least: we perceive three spatial dimensions plus time, and several other dimensions are postulated in modern theories), but that is really hard to draw in a 2-dimensional picture. To get around this, the above diagram actually represents space as 1-dimensional. At any moment in time, the universe is a slice of the funnel-shaped thing, which makes a circle. A circle is an apt analogy for the geometry of space. It is bounded in two dimensions, but in one dimension (as if you were traveling along the circle) it has no end. The laws of Relativity tell us that the universe similarly has a size in some sense, because it has been expanding at a finite speed for a finite amount of time, yet you can travel forever in any direction and never reach the edge. It simply doesn't have an "edge" in three dimensions.