The Nature of Scientific Inquiry; Is Evolution Science?

Hi Faith,I'm just replying to your most recent post, not to anything specific you say in it.I've read your posts from today, and there are three themes you address that I'd like to comment on:

1. Evolution can't be proven.
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2. Evolution isn't testable or replicable.
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3. We can't learn what happened in the past.

About the first one, yes, you're right, evolution can't be proven. But evolution is not alone in this sorry state. Relativity, gravity, wave/particle duality of light, quantum theory, radioactive decay, Maxwell's laws, cosmological expansion, and on and on through all the theories of all of science are in the same sorry state as evolution: they can't be proven. That's because all scientific theories are tentative. Something that is proven could not at the same time be tentative. Something proven could not be science.The confusion derives not because this is a difficult or subtle point (it isn't), but from simple differences in meaning. It all depends on what you mean by "proven". Like most words, "proven" has more than one meaning. One common dictionary definition of "proven" comes from GuruNet: Obviously this definition of "proven" is not compatible with being falsifiable. How could something that has been "verified without doubt" be falsifiable? So anyone speaking scientifically should not use the word "proven" with this definition in mind.But that's not the final word on the topic. There are more colloquial uses of the word "proven", and scientists and the people here are as prone to use the word in this way as anyone else, at least outside of technical papers. When someone speaking on matters of science says that something can be proven, they only mean that sufficient evidence can be produced to the point of being very persuasive. It is important to keep in mind that use of the word "proven" does not mean they believe something can be demonstrated or verified beyond doubt. No one familiar with science would ever imply this when speaking scientifically.So when you say evolution can't be proven, whether we agree with you or not depends upon how you define "proven". If by "proven" you mean demonstrated or verified beyond doubt, then we absolutely agree with you, evolution can't be proven. No scientific theory has been or ever will be proven.But if by "proven" you mean that convincing evidence cannot be produced, then we disagree with you. Mountains of very persuasive evidence for evolution are available.Now I'll move on to your point that I listed second, that evolution isn't testable or replicable. I can see by your reply to Schraf that you understand that it isn't events themselves that are replicable, but experiments and/or observations. You then conclude that therefore evolution isn't testable or replicable, but this misunderstands completely what a theory is.A theory is not a list of all the events that follow the theory. For example, Newton's Laws of Motion are not a list of everything we know has happened following these laws. Newton's Laws are precisely the opposite of such a lengthy and boring recitation. They are general principles expressed by simple mathematical formulas, like F=ma. Newton's laws are a way to interpret and make sense of the universe around us (Newton's laws must be augmented by relativistic considerations for high speeds or masses, but I want to keep the analogy simple).As accurate as Newton's laws are, that doesn't mean it allows us to figure out every event. For example, why did the most recent comet to visit the inner solar system come when it did? Was it pushed out of its orbit by a collision? By gravity from the close approach of another object? Is it just in a highly elliptical orbit of a very long period? We don't know. We may never know. There's simply not enough evidence to know. But we of course do not question Newton's laws just because there are some things for which the evidence is missing or unavailable to us.Unavailable evidence for specific situations is completely aside from any theory's validity. The power of a theory, in other words, its degree of acceptance within the relevant scientific community, is based upon the supporting evidence, which for Newton's Laws is massive.In the same way as Newton's Laws, the theory of evolution is not a list of things that have happened in evolutionary history. The theory of evolution, like Newton's Laws, is a set of general principles. Expressed simply, the theory of evolution is only descent with modification and natural selection. There is a huge amount of evidence supporting these principles. They were developed to explain the evidence. That is one purpose of theory, to help explain and understand evidence. A theory that doesn't correspond to the evidence is useless.There are many events of biological history we will never know because the evidence no longer exists. We have a general picture of a small part of evolutionary history based upon life today, the fossil record, cladistics, and genetic analysis. But so much evidence has been destroyed or permanently buried that the picture will only grow incrementally more detailed. You'll always be able to ask unanswerable questions, from small issues like what did Hyracotherium eat for breakfast, to profound questions like how did the human sense of curiousity and wonder evolve. The theory of evolution is an interpretive framework for evidence. About things for which is is little or no evidence we can only speculate. But that there are huge areas of missing or unavailable evidence is aside from the question of the validity of evolutionary theory. The theory of evolution is nearly universally accepted within the biological community because of the wealth of supporting evidence and because of the power of its explanatory framework.Now I'll address your point that I listed third, that we can't learn much about the past. I think I agree with most of your observations, which I think can be summed up as the further back in time something occurred, the less likely there is to be evidence sufficient to figure out what happened. But I can't see how any general conclusion can derive from this observation. Sometimes there's no evidence for a crime committed fifteen minutes ago. Sometimes entire frozen mammoths emerge out of the permafrost from 20,000 years ago, complete with fur, contents of stomach with local flora and DNA. Sometimes there are entire ecosystems that will be forever unknown to us, such as ancient upland regions which never get buried and leave fossils. And sometimes we find complete Tryanasaurus rex fossils with their last meal included.In this particular thread we're asking whether evolution is valid science. An assessment of your three points that I addressed in this post can be summarized as follows:

1. Evolution can't be proven.
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   Assessment: not a valid criticism.
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2. Evolution isn't testable or replicable.
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   Assessment: False.
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3. We can't learn what happened in the past.
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   Assessment: False.

--Percy

Hi Faith, Message 54 is actually for you - I somehow clicked on the reply button for Mark24's post.--Percy

Hi Faith,I'll let Mark24 deal with the specific cladistic issues. I think you asked just the right question at the conclusion of your post, about the specific morphological differents that are measured. I only wanted to comment on this portion to reinforce what I wrote earlier: The word "prove" or "proved" appears quite a bit in this passage. I won't belabor this since my previous post spends some considerable time on this point, so I'll just briefly reemphasize that we agree with you if by "prove" you mean verified beyond doubt. We only view the evidence from cladistics as verifying a specific prediction of evolution, that the succession of species found in the fossil record should follow an ordering that represents a hierarchical branching. The ability to make successful predictions like this is what gives a theory its power and cogency.There's a pattern to your posts where first you say you look at all the same evidence evolutionists do, you just interpret it differently, and then a short while later you say you don't accept the evidence. The way to properly assess competing theories is by contrasting how well they explain the various relevant evidence. This probably won't be possible for you if you dismiss all inconvenient evidence.The specifics of your posts lead me to the conclusion that the superficial you accept, the detailed you deny. You accept that fossils are in the geological layers, but you deny there's any order to them. You accept sedimentary layers, but deny that we can tell how they were deposited. You accept that radiometric elements are found in the ground, but deny there's any pattern with increasing depth.I think a healthy skepticism is a good thing, but be careful you don't cross the line from skepticism to denial and delusion. You are just as human as the scientists you think prone to judgmental error. Scientists do not have any monopoly on error, nor do Christians seem any less prone to error than anyone else.The only way you can determine if the evidence is wrong, or whether it really leads to evolutionary conclusions, is to examine it and evaluate it. If you instead dismiss evidence by convincing yourself that scientists are just assigning interpretations to evidence that lead to forgone evolutionary conclusions, then that would definitely be, in my opinion, a significant mistake.--Percy

All theories analyze the past and make predictions about the future. In the case of automobile accidents, the laws of physics are used to analyze the past, for instance, measuring skid marks and figuring out how fast the car was going based on its weight and the coefficient of friction of its tires with the ground. In the case of satellites, the laws of physics are used to predict the future, for instance to determine the necessary velocity vector to place a satellite in a stable orbit.But notice that the laws of physics (laws are just theories, by the way) are not about the past or the future. They're generalized principles that can be applied to analyze the past or predict the future. Evolution is the same as physics in this regard in being generalized principles. Simply stated, evolution is descent with modifification and natural selection. These principles in and of themselves say nothing about the past or the future, yet they enable us to analyze the past, just like the laws of physics, and they enable us to make predictions about the future, just like the laws of physics.Please let me know if my posts are too long or too difficult to understand or if something else is getting in the way, because I've explained this before in earlier posts, though not in the exact same words, and the point doesn't seem to be getting across.Once comment about the past. Everything we're aware of takes place in the past. Nothing ever happens in the present. By the time we're aware of it, the event is in the past. If you look at something about a foot away, that light takes a nanosecond to reach your eye. The chemical reactions in your retina, the signals along the optic nerve to the brain, the interpretation by the brain itself, take far longer, probably in the area of an additional 100 million nanoseconds (.1 seconds). By the time you're aware of an event, it is already in the past. This may seem like a niggling point to you, but it highlights a key issue: if being too far in the past is an impediment to applying the scientific process, how far in the past is too far?It's a rhetorical question you're not expected to answer. Its only purpose is to make clear there can be no line of demarcation between events young enough to analyze and events too old to analyze. Evidence, no matter how old, is still evidence, and evidence can be interpreted and analyzed. The more sparse the evidence, the more damaged or decayed the evidence, the more complex the analysis must be in order to tease out the implications. You can never conclude that something was too far in the past to study. That can never be a valid reason for not studying something. The only valid reason for inability to study something is the absence of evidence. The age of the evidence will only affect its quality and usefulness. Mere age by itself can can never preclude the possibility of study. But of course we can test them. Let me provide an example, one you've already seen before. Evolution predicts that the order of the fossils we find in the geologic layers should be increasingly different from modern forms with increasing depth. We can test this prediction by examining fossils from different geological layers. When we do this we find that, just as evolution predicts, the fossils are increasingly different from modern forms with increasing depth. Thus, evolution has made a successful prediction.This same test of the prediction could have falsified the theory of evolution, which is why the theory of evolution is considered falsifiable. Had we found that the geological layers did not contain the fossil progression predicted by the theory of evolution, this would be a falsification. Failing such a fundamental test would call the theory of evolution into serious question. Theories are general principles, not lists of historical events. Like all the scientific fields I listed, evolution consists of general principles, not a list of what has occurred throughout evolutionary history. The laws of physics can tell us when there were lunar eclipses in the first century AD, but the laws of physics are things like F=ma and F=Gm₁m₂/r², not lists of times of astronomical events. In the same way, evolution is the principles of descent with modification and natural selection, not a list of which dinosaurs lived in which eras. The theory of evolution has played a key role in helping us figure out the evolutionary past, and that's why its a valuable interpretive framework (which, by the way, is what a theory is).My earlier example of the automobile accident with the skid marks is a good example. Let us say that the automobile accident happened in Pompei, and just by sheer bad luck Mount Vesuvius decided to pick just that moment to erupt and bury the entire accident scene in miles of lava and volcanic ash. Thousands of years from now archeologists unearth Pompei (again) and uncover the accident scene with the skid marks. Just for the heck of it, the grad students on the archeological team decide to measure the skid marks to figure out how fast the automobile was going at the time of the accident, and discovering that he was over the limit (preserved on a sign nearby) by 20 km/hour, they issue the offenders skeleton (also preserved) a belated speeding ticket.The point of this story is to show how this auto accident that happened thousands of years in the past for these archeologists is still open to analysis because the relevant evidence has been preserved. Your division of the past into two eras, one era that's recent enough to analyze, and another era that's too long ago to analyze, does not correspond to the real world. The key factor governing whether some past event is open to analysis is how much evidence has been preserved, not how long ago it happened.Here's another example illustrating that your approach of using age to determine whether something is open to analysis or not is flawed, but this time in the other direction. In particle physics, things happen fast. Real fast. Huge devices accelerate particles up near the speed of light and then have them collide with one another to produce a spray of subatomic particles. Often these particles have extremely short lifetimes. In some cases if you wait even a nanosecond to measure the produced particles they'll already be gone. This is yet another counterexample to your view of things, in which a nanosecond ago is the virtual present and therefore open to study. But in this case a nanosecond ago is too far in the past. Your criteria of recent things being open to study again fails, this time in the opposite direction. You've again used the word proof, and I'm still not certain which definition of the word you intend. Do you mean "verified beyond doubt", or do you mean "supported by persuasive evidence"? You're correct, they can't be replicated, but I think everyone is puzzled why you think replication is necessary. An automobile accident that happened today can be analyzed by archeologists thousands of years in the future to figure out the speed of the automobile without replicating the accident. The operative factor is the availability of evidence, not the practicality of reenacting the entire event, and not how long ago in the past it happened. There's that word "prove" again. Could you at some point clarify how you're thinking of the word? If by "prove" you mean "verify beyond doubt", then we agree with you, past events can't be proved. Of course, all events happen in the past, so that would mean no events can be proved. It's far more practical, and it is in fact the practice within science when speaking casually, to define the word "proof" to mean "persuasively supported by evidence."--PercyThis message has been edited by Percy, 04-11-2005 01:42 PM

I think a healthy skepticism is a good thing, but be careful you don't cross the line from skepticism to denial and delusion. You are just as human as the scientists you think prone to such simple process errors. Scientists do not have any monopoly on error, nor do Christians seem any less prone to error than anyone else.The only way you can determine if the evidence is wrong, or whether it really leads to evolutionary conclusions, is to examine it and evaluate it. If you instead dismiss evidence by convincing yourself that scientists are just assigning interpretations to evidence that lead to forgone evolutionary conclusions, then that would definitely be, in my opinion, a significant mistake.--Percy

Hi Mark,At the end of Message 57 Faith asked about the morphological characteristics used in cladistics. It might be helpful if you provided an example or two of specific morphological characteristics and how cladistics organizes them to find correlations with the fossil record.--PercyThis message has been edited by Percy, 04-11-2005 01:46 PM

Well, yes, but as Linear pointed out, it isn't clear she understands the evidence derives from independent sources. Plus it was a question she specifically asked. Why wouldn't you answer it? If cladistics is your thing, then why wouldn't you take every opportunity to tell anyone who expressed an interest anything they wanted to know? Sure, give it a shot, but define phylogeny first.--Percy

Hi Mark,Not to get into a meta-discussion, but I just don't follow your logic. And if I who accept your cladistics argument don't follow your logic for not providing more information and explanation, then Faith who rejects your argument certainly doesn't follow it.I don't think you comprehend the depths that lack of scientific knowledge and thinking can plumb. I think you underestimate the myriad of ways scientific explanations can be misunderstood or not understood. The only prayer you have of success is to explain the same thing in as many different ways as you can as many times as you can as patiently as you can. You've got the attention of a Creationist with a keen mind, don't squander it.--Percy

Can you describe how this simplified cladogram example correlates with stratigraphic evidence to provide supporting evidence for evolution?--Percy