This is my second post where I'm writing, for my own reference, the response to one of the old and hoary creationist canards that are brought up in response to things like my long letter to the editor published in the Tennessean, as part of a segment on the question "should you take your kids to the Creation Museum?".
I will quote from one of the letters I received to give one version of this argument:
Science, by definition must be observable, measurable (testable), and repeatable (reproducible).
Neither creation nor evolution can be observed. Both are done. By evolution, we must specify macro evolution and not minor adaptive modifications. Change must involve gene or DNA modification to qualify as an evolutionary development. Cross breeding or hybridization is also not evolution. All we "see" or observe today is modification: no true evolution.
The general argument is that evolution is no more scientific theory than creationism, because both are dealing with past events that cannot be addressed in the scientific laboratory. Sure, we've seen evolution in the lab— consider the prevalence of antibiotic-resistant bacteria today, clear evidence of bacteria which have evolved in the face of a change in environment (i.e. an environment awash with antibiotics). But creationists call this "microevolution." They say that changes between species as described by the theory of evolution happen on such a long timescale that we can't do experiments, and that as such, according to them, evolution doesn't obey the rules of science. So, they say, evolution is just as much faith as creationism, and the two should be treated equivalently.
They are, of course, very wrong.
Instead of biological evolution, I'm going to talk about astronomy. It's my field, so I'm more qualified to talk about it. Plus, it is subject to exactly the same objection. In particular, I'm going to talk about stellar evolution. We understand that it takes a star like our Sun about 10 billion years to go through its live cycle. Even a very massive "short-lived" star takes a few million years. Obviously, we do not have observations of a star going through this whole cycle! How, then, can we claim to know anything about these times of timescales? To paraphrase a presidential candidate (who was echoing legions of creationists) we weren't there. Because the theory of stellar evolution predicts these things, is it even science at all? After all, we cannot do any sort of repeatable experiment where we make a star and watch it go through its lifetime, measuring how long it takes, given that (a) stars mass millions of times more than the Earth, and (b) stars live millions of times longer than any the time of any practical scientific experiment.
The answer is that this is a very narrow view of science. It is, alas, a view of science which is easily inferred from the definitions of the scientific method most kids are taught in middle and high school classes. You start with your hypothesis, you design an experiment, you perform the experiment to see if the results match your hypothesis, and you draw conclusions based on that. Then the experiment needs to be repeated, ideally by different scientists using different experimental techniques, to make sure that it wasn't something wrong with your lab procedure.
All of that is great, but that's not all of science.
"A scientific theory must predict the outcome of a future experiment," creationists will always say, "so evolution (or stellar evolution) is no more a scientific theory than creationism, because all of those things are talking about things that happened int he past.
Here's the thing, though: a legitimate scientific theory can produce the results of a future observation of a past event, be it something in the fossil record, or observations of an astronomical object that are far enough away that the light took many years to reach us. Scientific experiments are not limited to things performed in the lab, under conditions controlled by the experimenters. A scientific experiment can also be a design of a set of observations— including the selection of the sample of objects or things to observe, the nature of the observations to be made, the way in which the observations will be analyzed, and the way in which that analysis will test a hypothesis. Those observations can be of things that are just "out there" for us to see. Just about all of astronomy works that way.
So, for example, we have models of stellar evolution which are built from the theory of stellar evolution, processed through some necessary assumptions (because while the theory is great, our understanding isn't perfect) and large numbers of calculations. This model can, for example, predict the colors and brightnesses of stars all formed at the same time 13 billion years ago. If you have stars of a bunch of different masses, and plot their colors and brightnesses, this theory of stellar evolution shows them falling not randomly about the plot, but in a very specific pattern.
If you then compare that pattern to what you see if you measure the colors and brightnesses of stars in a globular cluster, you find a remarkable match. What does this tell us? This tells us that we have an explanation for why the stars in the globular cluster have the colors and brightnesses that they do. It's because stars go through their lifetimes in this particular way... a way that takes billions of years for it to happen.
The theory of stellar evolution is rock solid. There are huge numbers of observations that confirm it. Everything that we understand about stars. all of the observations we make that include starlight, are implicitly or explicitly testing this theory all the time. And it is proper science. Never did we make a star and watch it go through its life to see if it did what the theory told us it did. But we did find collections of stars to test if they look the way the theory said a collection of stars should look.
Historical sciences are legitimate sciences. The theories can be rigorously tested by scientific observations, just as the predictions of chemistry theory can be rigorously tested by laboratory experiments. This includes most of astronomy, geology, physical anthropology, and paleontology, and much (though not all) of evolutionary biology.
In this way, evolution does not depend on Faith at all. It's not just somebody's idea about what happened. It's a theory that makes quite a number of predictions on many different levels, all of which have been borne out by observation. Be it the similarities and differences in the genetic code of animals that are more similar or more different, be it the rapid evolution of bacteria or birds that scientists have observed, be it the ancestry of modern humans as traced through the fossil record, evolution is something that explains observations, just as assuredly as nuclear theory explains observations made from experiments with cyclotrons.
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Rob: Woo, first post on your blog!
An alternate way of looking at it isn't that complexity is desirable per se, but that it sometimes enables the conquest of new niches. Simple bacteria can be damned successful (hell, there's a good argument that they're still the most successful lifeforms on the planet), but they can't get ahold of *everything*. There were untapped vistas just waiting to be exploited, and they were.
And then, of course, complexity wrought new niches where there were none before (how could there be a niche for animals who eat fruit grown in the top branches of a tree before there were trees and fruit?), causing the evolution of further complexity when necessary...
I'm certain you know this, and your comment implies that you see the same things I do, but I just thought I'd elucidate it more thoroughly.
Rob, thats all very well, as it goes but it ignores one of the basic underpinnings of any modern scientific theory, the whole notion of uniformitarianism. If one rejects that idea and instead believes that conditions, physical forces etc, were different at various points in the earths history then any experiment we do today will have little meaning when trying to interpret past events. The observation that light travels 186,000 miles per second in a vacuum tells scientists that light from distant stars must have taken millions of years to reach us only if we accept that light has always had this speed limit. If this speed limit was different in the past then it could explain why the light could have taken less than 6000 years rather than the millions that todays theories predict. The same goes for any other discrepancy that creationists bring up. If one rejects uniformitarianism then it is certainly possible to rationalize any current observation with the idea that 'God' altered the conditions in the past for a specific purpose and current experiments are useless to prove or disprove this idea.
Of course there is a dilemma here. Most religions also teach that 'God' occasionally does change the laws of the universe for his own mysterious purpose, whether is it to part a sea, have a virgin give birth, bring a man back from the dead or have a man fly up to heaven on a winged horse. If one allows exceptions such as these then why not other exceptions such as a different speed of light, a global flood or a six day creation ?
If one rejects uniformitarianism then it is certainly possible to rationalize any current observation with the idea that 'God' altered the conditions in the past for a specific purpose and current experiments are useless to prove or disprove this idea.
If you're going to do that, then you have to change a whole lot else to make all sorts of observations of our Galaxy, never mind our Universe, be what they are. Observations of galaxies at distances of millions, even billions, of light-years show us that atomic physics worked pretty much the same way. That would not be the case if the speed of light was changing.
I know that "changing speed of light" is something that creationists try to pull out in order to reconcile their idea of a 6000-year-old Universe with clear evidence to the contrary, but it simply does not work.
If you're going to start going that route, you're in for a huge mess unless you go all the way and resort to a "brain in a box" model. Creationists made more sense when they tried to assert that all the evidence for an old Universe was there to test our faith, instead of trying to come up with scientistic-sounding ways of shoehorning it all together. Sorry, dude, but it's all nonsense.
-Rob
Great post. I'll definitely incorporate this argument into my ongoing debates with my creationist friends.
Of course its all nonsense. You, I and those that accept the scientific method know that, but the reason we believe it is nonsense is that we accept that there is no evidence that the physical laws we have deduced from centuries of experiment and observation have been different in the past.
Scientific observations have not given us reason to believe that there can be any temporary alterations to these laws. In other words miracles don't fit in with how our observations tell us the universe works. If you are prepared to allow one miracle then uniformitarianism breaks down and in that case why not two miracles, three or the whole bible?
The historical science concept is AFAIK originally pointing out constraints of repeatability, variation and observability: it is generally harder to get complete observations, sometimes these are singular events et cetera.
But the whole "where you there" idea is perverting this into meaning that scientists must observe and analyze stuff in real time, while we can argue that there is always a light speed delay however small (or long). Especially for evolution, since parts such as population genetics is observable as it happens.
I find the similarity between drawing magical barriers for delays and magical barriers for evolution both hilarious and sad. And likewise the preferred reliance on the real historical record of interpreting different old texts into different dogmas instead of using fresh observational data into testable theories.
Oh, and of course we can repeat observations in natural historical sciences too, for example by observing several similar stars or fossils. The simile is so misapplied it isn't even wrong.
Ha! I don't have time to read this all right now, but the title of this post reminds me of when my brother, who studies history, called me one night to verify that astronomy is indeed a science even though we can't "run experiments" (much like, oh, say, history).
Re speed of light was much faster in the past.
1. This is an example of the old saw that there is no such thing as a free lunch.
If the speed of light was much greater in the past then it is now, we have a severe problem with the effect of the energy produced by the sun. Using Einsteins equation E = mc^2. we see that photons produced by the conversion of nuclear binding energy in the sun through thermonuclear reactions also had far more energy then they currently have. The result of the earth being bombarded by photons with millions of times the energy as currently would instantly boil off the earths atmosphere and liquid water and turn the earths surface into something resembling the surface of the moon. Not very conducive to creation of life.
2. Prof. Knop might be interested in a running discussion on a thread on Jason Rosenhouses' blog involving a YEC calling himself Jon S who invokes a hypothesis proposed by somebody named Russell Humphreys which appears to be based on the notion of gravitational time dilation, and purports to explain how light from galaxies millions and billions of light years away arrived in 10,000 years. It might possibly be of interest to his readers for Prof. Knop to debunk this hypothesis as I and other commentators really didn't have a sufficient understanding of General Relativity to do a good job.
http://scienceblogs.com/evolutionblog/2007/05/the_times_on_the_creation…
Just ask them about the fruit flies.
Just ask them about the fruit flies.
Fruit only flies when you throw it, and then that's all about gravity....
-Rob
Someone's already brought up E = mc^2. I'll bring up c = 1 / sqrt(epsilon_0 * mu_0). This is one of the most famous results of 19th-century physics: the speed of light, and electromagnetic waves generally, is directly related to the sizes of the two constants that define the strengths of electromagnetic interactions. So let's say you change epsilon_0. Congratulations, that's equivalent to changing the constant in Coulomb's law for the force between electric charges. So you've radically changed all of chemistry. And all of stellar evolution (fusion rates in stars are limited by the strength of the repulsion between nuclei).
In case it's not already clear, we'd see the effects of that change, in areas seemingly unrelated to light travel times, and they wouldn't be subtle.
IANAS, but I thought that the discovery of Tiktaalik was a perfect example of an experiment in evolution. The theory predicted that an intermediate fossil would be discovered in rock of a certain age formed under certain circumstances. The experiment: Find rock that fits the criteria and search for fossils. If there's an intermediate form, the experiment is a success and the theory is confirmed. Tiktaalik was discovered exactly where they predicted it would be discovered. Experimental science, QED.
The discovery of Tiktaalik certainly qualifies as good observational science, but I think its debatable that it qualifies as an "experiment" in the strictest sense of that word. Experiments usually have controls, and they have independent and dependent variables.
You could I suppose call it a non-controlled natural experiment. At the risk of some Creationist insisting there must be an Experimentor.
in the language of the original post, I'd call the discovery of Tiktaalik an "observation." As Dave said, it wasn't an experiment in the traditional "set up in the lab" case, but something that was predicted should be found.
Astronomy works the same way. There, generally, we do need a control sample for our observations, if we're testing something that is supposed to be different from the general population. But the theories predict what should be seen, and we go out and do the observations to see if we see them.
-Rob
Re HP, Dave S and Rob Knop
The predictions lead to the notion of falsification. If a theory predicts something and that something is not seen, the theory has been falsified, at least as formulated. Example, time dilation in special relativity. This was predicted in 1905 but wasn't actually directly observed until the early 1950s when it was observed that the mean lifetime of fast muons were much longer then slow muons when produced in a synchrotron.
Since no one's used it yet, here's one of the discussions of speed of light/ radioactive decay at talk origins: http://www.talkorigins.org/origins/postmonth/oct01.html.
Two birds, one stone (or supernova).
mollishka:
Sure you can run experiments in Astronomy! You just need to get a pair of Acme, Inc. black holes and crash them together. I admit that experimental astrophysics is still in its infancy, but we're always looking for funding. We've almost got enough to bang a couple of asteroids together.
(Removes tongue from cheek.)
Nice post, Rob. Pity it won't shake any of the True Believers.
Great post and even even better responses. Loved the use of E = mc^2 and c = 1/sqrt(epsilon_0*mu_0).
No one however has responded to Rob's point that creationists are using middle school definitions of science and experiments. Well, duh...
Ever examine closely what other science education the majority of Americans get? It usually stops at about middle school. Maybe you take chemistry, physics of biology in high school, but even there, you pretty much stick with the basics: start with your hypothesis, design an experiment, perform the experiment, and check your hypothesis.
No wonder most Americans think that's what science amounts to. Like I said... duh!
Two points require a response. First, concerning the "stellar evolution" model Dr. Knop cited. Second is the misnomer of "bacterial evolution" with regard to antibiotic immunity.
The stellar evolution is an interesting example of faulty reasoning. This is a very elaborately devised explanation for the observations of differences in stars. The observation is that stars differ brightness and color. The question is, "Why?" The answer (theory) is that the masses, color, and brightness are related. So a method is devised to account for mass, color, and brilliance. Then the flaw in the reasoning was revealed.
Assuming that all of the stars were formed at the same time, 13 million years ago.... We do not know that. That is part of the original assumptions used to devise the scheme. Now, assuming the assumptions, the theory proceeds to plot the stars, masses, and brilliances. Voila! They fit the pattern.
In argumentation, this is called circular reasoning. Here is a simplified example. We observe that some stars are red and others more bluish. Our theory is that red stars are older and blue stars are younger. So we classify stars that are blue as young and red as old. Then we examine the pattern of stars going from red to blue and conclude that indeed the oldest (lowest on the chart) are older than the higher, blue ones. This then proves the theory as all of the old stars (lowest on the chart) are clustered at the bottom and the youngest, blue stars are at the top.
We have used our observations to both propound a theory and to prove the theory once it has been promulgated. Circular reasoning.
Second comment: The evolution of immunity to antibiotics has often been touted as definite proof of evolution. It is nothing of the kind. I will use mosquitoes as a more visually defineable example.
When DDT was first sprayed on mosquito populations nearly all of them were susceptible and died. But, some had a natural immunity and survived. Needless to say, only the survivors reproduced and the ensuing populations contained many more individuals which possessed immunity to DDT. Those who were not immune were eliminated and only the immune population survived and again reproduced.
After several generations, nearly the entire population was immune. In other words, the "population" had developed immunity. But no individual developed an immunity. It was either inherent or the individual was extinct.
There was no DNA development or degradation. The proper term is expression of characteristics. The population became adapted or acclimatized, but no evolutionary development occurred. This is not even "micro-evolution." Each individual was exactly as his DNA defined.
DNA is the death of evolution. Simple one celled organisms have more DNA than a human. Other, similar organisms have less DNA than humans. An evolutionary chain would presumably involve simple DNA for simple organisms and increasingly complex DNA as the organism developed.
And how does DNA change in the first place? It only changes in a degradative direction. That accounts for aging. If evolution depended upon DNA, it would be devolution. Organisms and systems can degrade, but none have been shown to spontaneously develop in a positive direction. They may grow or get bigger, but they do not develop additional characteristics. Mutations are invariably deleterious if not lethal.
The case for evolution is far from proven. In fact, it seems to be following the flow of entropy and our old friend, DNA.
Thank you for your consideration.
In argumentation, this is called circular reasoning.
No. It's called fitting with one (or a few) free parameters, and is an *extremely* standard procedure in science.
You have a bunch of data along a line. You run a fit to it, and can extract the slope and intercept of the line. You can also see how well the data matches to the line.
The fact that the slope and the intercept are free parameters of the fit does not at all undermine your ability to determine how well a *line* fits the data.
The stellar evolution models work exactly the same way. What's more, they're way deeper and based on physics in a way that your straw-man "theory" of "young blue, old red" does not.
I submit that you really do not know what you're talking about in attempting to poke holes in this.
DNA is the death of evolution.
Wow. You really don't know biology, at all. No more comment is warranted on any of that line!
-Rob
First, a conclusive test on a theory is on predictions for new data (observations).
Second, the description of circularity or tautology for a model (theory) is complicated and not harmful (since we test on other data, see above).
A theory must by definition be tautological on the data it describes, since the data is true and the theory describes the data truthfully. I.e. we can always make a tautology by adding mechanisms. But the essential thing is that this is not a priori true, which is why we can test on new predictions.
Also, data is lifted up from observations to test the theory. New data can always invalidate a theory as well, for example by showing that old data used for the model was incomplete or erroneous.
What do you think changed in the population? The alleles of the genome - genes expressing characteristics that made individuals immune was kept. That is called "selection", on preexisting and concurrent variation. (Every individual have a few mutations due to the large amount of DNA.)
Rob is correct, you need to look at basic biology if you don't know about mutation and selection, for example at the Talk Origin site. Because what you now show is laughable.
You will find that there are no magical barriers between small and large accumulations of characteristics change. If anything, macroevolution of populations add some evolutionary mechanisms such as group selection.
You will also find that the amount of DNA is explainable with cell size, not organism size, junk DNA making up the 'filler' since handling DNA energetically seems to be 'noise' in the cells energy budget and evidently of little consequence in selection.
Cell size is selectable for different reasons. For example single cell organisms that predate on others by enveloping them must be larger to feed, while small and efficient red blood cells in humans lack DNA.
And you will find that there is no 'ladder' or 'chain' of evolution. Evolution is a symmetric process without preferred direction and is observed to make new species more simple or more complex compared to the ancestral species.
The sheer amount of single cell organisms implies that it is easy to lose characters that aren't strictly necessary, and that is often seen. Complexity is, as all other characteristics of evolution, contingent.
And you will find that there is no 'ladder' or 'chain' of evolution. Evolution is a symmetric process without preferred direction and is observed to make new species more simple or more complex compared to the ancestral species.
Hmm... this isn't completely right. At least in early times, there were advantages to being more complex. This is why life progressed past the stage of single-celled organisms. I supposed it's possible that the complexity that evolved is consistent with a "random walk" type of symmetric pressure, but I'd be surprised if that were the case.
Certainly the development can go in either direction, but depending on the environment and the other organisms present, there may be a systematic difference in the natural selection pressures in one direction or the other.
-Rob
I'm always prepared to be wrong, especially here as a layman on this subject, but in fact I'm not sure if anyone has worked out any directionality in evolution. (But I bet astrobiologists would like to know. :-) I believe I have seen several biologists claim that complexity, or at least intelligence, is coincidental.
My naive take on this is that we had an asymmetrical initial condition, in simple single cells, whether or not the process is truly or roughly symmetrical. "Diffusion" would do the rest, whether or not there was initial advantages for complexity or not.
If there really is or was a systematic selective pressure on single cells, I don't know. I have seen three or four descriptions that I think could be described as directionality or regulation.
First, coevolution and/or niche filling. For single cells that could be evolution of predation, where the predator would first gain on being larger (for enveloping) and more "intelligent" than the prey.
Second, structural constraints, for more complex organisms I think. Having a characteristic it is hard to drop it, so it will be modified, sometimes as an adaption.
Third, evolving evolvability, selection et cetera resulting in regulating variation rates that fit selective pressures et cetera.
But I don't think any of these answer why multicellularity and more complex individuals evolved.