The Three E's : Evidence, Evolution, and, um, Eggs

CoIin
CoIin: It seems that everyone and their pre-Cambrian rabbit has a thread on evolution these days, so not to be outdone...

My intention in this thread is to identify and correct certain prevalent, but overly simplistic, notions regarding scientific theories and the manner in which evidence relates to them. This may be of particular interest to those of us who enjoy following, and perhaps contributing to, the various threads on that perennial Wireclub favourite - Evolution - which run the gamut from frivolous to thoughtful.

It's critical to emphasize at the outset that when a scientist stops talking about the nuts and bolts of a particular scientific theory, say evolution, and starts making assertions on how well confirmed the theory is, or how likely the theory is to be true, or dismisses a rival theory as pseudoscientific, and so on and so forth, she has abandoned her own area of expertise - SHE CEASES TO DO SCIENCE - and now trespasses on philosophy of science turf. Scientists don't get paid to think about conceptual issues such as those just mentioned; philosophers do.

Scientists are perfectly entitled to express opinions on extra-scientific conceptual matters, as are we all, but it would be a grave mistake to think that scientists themselves are the most knowledgeable people on these matters. Scientists (and science fans) can, and often do, make assertions about their own theories, and about the history and nature of science in general, which are liable to induce an epileptic fit in any logician or historian/philosopher of science worth his sodium chloride.

We would be foolish indeed not to listen to what scientists have to tell us about the world. Having said that, I'd caution the reader against heeding too seriously the pronouncements of scientists on matters other than actual science. This, surely, is no more than common sense demands.

Any sensible contributions or criticisms are welcome.
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CoIin
CoIin: To work! First of all, then, let's examine a typical claim:-

(C1). There is a mountain of evidence supporting evolutionary theory. In the space of 150 years, no real evidence has been found which militates against it.

A persuasive claim, you may well concede while nodding approvingly. Well, what I'd like to do in this opening post is show that this is actually a much weaker claim than appearances might inveigle us into believing.

A caricature might help in illustrating the WRONG way to think about these matters. Imagine a guy sitting at a desk. This guy is the theory arbiter. At the start of each day he finds a pile of reports in his "IN" tray. These reports are the evidence relevant to the theory in question. The guy examines each report, performs a little number-crunching and logic-chopping, eventually stamping each report with "CONFIRMS THEORY", i.e., good news for the theory, or "FALSIFIES THEORY", in which case the theory is a goner.

Now, if this was an accurate characterization of the way theory appraisal is actually conducted, and evolutionary theory (or any other) had been tested in this way for over a century with not a single "FALSIFIES THEORY" anywhere in sight, then a result such as this would indeed be singularly impressive.

Sadly, as you'll have anticipated by now, the above scenario bears little or no resemblance to real world affairs.

We need to get over the notion that evidence can falsify a theory in any definitive manner. In the empirical realm of science, evidence almost never stands directly in contradiction with theory in the way that, say, 2p=7 is logically inconsistent with p=5.

To a first approximation (expansion forthcoming - stay tuned! ), then, what we CAN say with confidence is that all evidence examined thus far is "compatible" or "consistent" with evolutionary theory in the sense that no contradictions are thereby generated. But what I hope to make clear is that a claim of compatibilty or consistency is, in and of itself, AN EXTREMELY WEAK CLAIM.

Another illustration might help. Let's take Newton's three laws of motion combined with his inverse square law of gravitation and call this "Newtonian Physics" (NP). I now submit to you that NP is consistent with absolutely any observational evidence whatsoever. Put differently, there is not a single observation that would constitute a contradiction of NP.

Don't believe me? Well, feel free to offer counterexamples. How about the discovery of a planet with a rectangular orbit? Or a figure-of-eight orbit with fits and starts along the way? Would these observations/evidence be inconsistent with Newtonian Physics as defined above? If you think so, please elaborate.

How about this scenario: you're holding an object in your hand. You release the object. The object "falls" upwards. Is NP now definitively refuted? Does it make any difference if the object is an egg or a eaglet?

Homework question : Is Newtonian Physics, as defined above, falsifiable?

I'll have much more to say on this, but first a pause to let the point sink in. Later, perhaps, we can examine how this relates to evolution and other theories, and whether or not that much vaunted pre-Cambrian rabbit really is inconsistent with (i.e. falsifies) evolutionary theory, dubious pronouncements to the contrary from Richard Dawkins et al notwithstanding.
(Edited by CoIin)
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duncan124
(Post deleted by CoIin 9 years ago)
calybonos
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ghostgeek
ghostgeek: Are you sure they had rabbits in the pre-Cambrian era? I thought magicians only started using hats in recent times.
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calybonos
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CoIin
CoIin: As far as we know, there were no rabbits in the pre-Cambrian.

The point of all this - and I thought it was well known ( ) - is that the accusation of unfalsifiability has at times been levelled at evolutionary theory, often by Creationists wishing to give the scientists a taste of their own medicine, perhaps. The evolutionists (Dawkins et al) insist that their theory is falsifiable.

What would falsify it then?

Enter that scrawny pre-Cambrian rabbit

Now, the question for us to consider here is: what are we to make of Dawkins' claim. What exactly is he saying? Is he claiming

(a). a pre-Cambrian rabbit fossil would stand in contradiction with evolutionary theory. The two are logically inconsistent.

(b). If a pre-Cambrian rabbit fossil were unearthed, Dawkins would abandon the theory. (This amounts to one man's promise. It says nothing at all about any intrinsic falsifiability of the theory.)


Let the readers vote...
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calybonos
(Post deleted by calybonos 9 years ago)
CoIin
CoIin: What would a talking pig in a cave painting look like?

Would there be a bubble coming out his mouth?
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calybonos
(Post deleted by calybonos 9 years ago)
CoIin
CoIin: Hey Caly. I like it when you get serious. You're an extremely insightful kinda guy, I mean pig

This goes for Ghostgeek too. I always enjoy reading your posts. You both exhibit good common sense unskewed by overenthusiasm to a particular hypothesis or worldview, which of course means that you don't end up painting yourself in a corner defending ludicrous consequences.

Be serious, damn pig!
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calybonos
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ghostgeek
ghostgeek: I sometimes think we're the most insightful when we're being the least serious.
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CoIin
CoIin: Answer to homework question : Newtonian Physics (NP) is consistent with ANY observational evidence, or "facts", if you prefer. As a matter of simple logic, it is falsified by no observation whatsoever. The theory as I've defined it, then, is unfalsifiable. Newtonian Physics is compatible with any imaginable motion, orbit, trajectory, or flightpath just as long as the appropriate forces are at work.

(We might note that NP, although consistent with absolutely any observational evidence, is not necessarily consistent with other THEORIES. For example, Newton's Second Law, F=ma is quite clearly in contradiction with, say, Fsquared = ma.)

Once again I emphasize, if this makes you uneasy, then feel free to offer up counterexamples. Later, perhaps, we can analyze evolutionary theory (ET) in the same way. To do that, of course, we'd need to know precisely what ET is. Without a written manifesto we can't possibly ascertain its falsifiabilty status.

Now, a scientist (Dawkins) might announce a promise to the effect that if certain evidence is found -- that pre-Cambrian rabbit, say -- he'll abandon the theory. And that's all very well and good. That said, a man's word of honour, quite obviously. has no bearing whatsoever on the intrinsic falsifiability of a particular theory.

So, getting back to the original claim for evolutionary theory we were examining in the opening posts, to wit:

(C1). There is a mountain of evidence supporting evolutionary theory. In the space of 150 years, no real evidence has been found which militates against it.

Now we see that if by "militating against it" the claimant means "falsifies the theory", we should not be overly impressed. It may well be the case that the theory CANNOT be falsified, assertions to the contrary from scientific superstars notwithstanding.

The logic behind this is very simple. You can do it as well as I can, and apparently better than Richard Dawkins can. I invite the reader to make up his/her own mind.

Tune in at the same time tomorrow.
(Edited by CoIin)
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Bourbaki
Bourbaki: bump
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CoIin
CoIin: Bourbaki

Any thoughts so far? I'm always glad to know that your logical mind is casting a critical, er... mindseye over the proceedings.
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Bourbaki
Bourbaki: I don't have anything particularly interesting to contribute for now. I want to see where you intend to take this thread =)
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CoIin
CoIin: I was thinking of taking her to the beach today
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CoIin
CoIin: Well, what I'm going to try and do in the thread is build a case that the common test-and-falsify image of science that most people have is hopelessly inaccurate.

I'll present a different model of science wherein the main activity of science consists of MAKING EVIDENCE FIT THE THEORETICAL FRAMEWORK. (and this needn't be read in an overly cynical manner). Evidence normally doesn't just simply fit or fail to fit, thereby confirming or falsifying a theory, but rather will be MADE TO fit. Or at least they'll burst a blood vessel trying.

And after all that, if something STILL doesn't fit, I suggest it's still highly unlikely that you'll hear any declarations of falsification and theory abandonment. More probable, as history can attest, is that the recalcitrant evidence will simply be stuffed away in a closet somewhere like these ghastly ties Aunt Martha keeps giving you on birthdays.

A lot of people out there seem under the impression that scientists are continuously testing their most cherished theories, striving to "destroy" them, as one member put it. This is, of course, sheer fairy-tale nonsense, belied by a simple review of scientific history.

A firmly established paradigm such as the current evolutionary synthesis, although in principle tentative and revisable, in practice can be regarded as a GIVEN. It is not in doubt. Scientists spend their time finding ways to fit evidence into the framework. The framework itself is, to all effects and purposes, not under test.

A question : You see a magician (or a yogi in India) levitating. Does it even ENTER YOUR MIND that the laws of physics are in jeopardy? Are the laws of physics "under test"? Would you even for one second entertain such a notion?

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CoIin
CoIin: That man Popper has a lot to answer for, I tell ya!
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CoIin
CoIin: What's also rather ironic in all this is that scientists can often be seen accusing the religious of cherry-picking, inconsistency, picking-and-choosing, etc. etc, and the charge is indeed well founded. The religious are perfectly willing to invoke scientific findings when it suits their agenda and dismiss them otherwise.

Well, I think you'll find scientists do precisely the same thing vis-a-vis philosophy of science. In one breath they're likely to dismiss it as a load of bollocks . In the next you'll hear them waxing lyrically on their much beloved doctrine of falsifiability.

Well, where, I ask you, did this doctrine come from originally?
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CoIin
CoIin: An Interlude - Popperian Polemics

Prior to embarking on a pilgrimage or pawning the family jewels to construct a Popperian shrine, those disposed to eulogize Karl Popper for his doctrine of falsifiability may wish to peruse his thoughts on scientific method below (from "Realism and the Aim of Science" ) :-


"As a rule, I begin my lectures on Scientific Method by telling my students that scientific method does not exist. I add that I ought to know, having been for a time at least, the only professor of this non-existent subject within the British commonwealth.

[...]

What I mean is this. The founders of the subject: Plato, Aristotle, Bacon and Descartes, as well as most of their successors, for example John Stuart Mill, believed that there existed a method of finding scientific truth. In a later and slightly more sceptical period there were methodologists who believed that there existed a method, if not of FINDING a true theory, then at least of ascertaining whether or not some given hypothesis was true; or (even more sceptical) whether some given hypothesis was at least 'probable' to some ascertainable degree.

I assert that no scientific method exists in any of these three senses. To put it in a more direct way:

(1) There is no method of discovering a scientific theory.
(2) There is no method of ascertaining the truth of a scientific hypothesis, i.e., no method of verification.
(3) There is no method of ascertaining whether a hypothesis is "probable", or probably true.

[...]

I believe that the so-called method of science consists in this kind of criticism. Scientific theories are distinguished from myths merely in being criticizable, and in being open to modifications in the light of criticism. They can be neither verified nor probabilified."




This vagabond claims there is no method for discovering theories, no method for verifying their truth, and not even a method for gauging how probable a theory is. Well, well, well! If this is indeed the case, why is it we keep being told that evolutionary theory (and other theories) are "probable", or "very likely to be true", or even just plain TRUE?

I invite anyone who finds these conclusions unpalatable to come forward and expose the dastardly cad for the charlatan he surely is!
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ghostgeek
ghostgeek: I have a theory that if somebody runs full-tilt at a brick wall, when they make contact with it, they will be hurt. This theory of mine was discovered by accident, is I believe eminently verifiable and, given the characteristics of brick walls, has a high probability of being correct. All I need now is a volunteer to test it out.
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CoIin
CoIin: Ghostgeek

Nice thought

Well, let's try applying Popper's insights to your theory.

1. How was your theory generated? Was it generated METHODICALLY or did it just kinda "pop into your head"?

2. Is your theory true? Your post implies you'll settle for probability over truth. Right? So we can skip 2.

3. You suggest your theory has a "high probability of being correct". Is this just a gut feeling? Or can you demonstrate this with mathematics?


Actually, you raise a rather disturbing point. As I've mentioned above, it's commonplace to hear scientists or science fans assert that evolutionary theory (and others) is true, or likely to be true, or probably true. But as in your own case, it's clear this intuition is not supported by logic or mathematics.

In fact, it IS possible to put a probability on your theory. If you're making a general claim , a UNIVERSAL claim, "this is what ALWAYS happens: anyplace, anytime" -- and scientific theories are universal in this way -- then in order to prove your theory we would need to examine EVERY case, i.e., an infinite number. Now, no matter how much evidence you gather, i.e. no matter how many times you test your theory, the ratio of examined cases vs total cases will always be a finite number vs an infinite number, hence ZERO.

Here's how philosopher Imre Lakatos puts it:-

"The only embarrassing thing is that in 1925 Ritchie showed that the probability of H, given E, equals zero, for any hypothesis and any evidence whatsoever. Intuitively this is crystal clear. What is a scientific hypothesis? A scientific hypothesis says something about the world. For instance : "All bodies attract each other according to the inverse squared law". The information content of such a theory is enormous. A piece of evidence is one piece of factual information about something with a spatio-temporal coordinate, i.e. a little bit of the universe. So it is quite clear that if we agree that all events are equi-probable, we have infinitely many events which add up to a scientific theory and therefore, since we are capable of producing only a finite amount of evidence, the probability P will always be zero. This is what Ritchie showed."
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CoIin
CoIin: P.S. @ Ghostgeek

I recommend conducting tests on Calybonos first. Pig flesh is apparently very similar to human flesh in constitution and strength (well, Mythbusters always use pigs anyway ).

If he's not available, we'll use Donald Trump.
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ghostgeek
ghostgeek: Colin, you ask how my theory was generated. I can say emphatically it was derived from hard empirical evidence, usually involving my head coming into contact with something unyielding. As each instance of this resulted in a sore head I'm inclined to believe that any future instance will also result in considerable discomfort. Of course, I'm willing to entertain the possibility that I might be wrong, thus the need for a volunteer to keep banging his or her head against a brick wall. It may, after all, be the case that if performed a sufficient number of times this action promotes a feeling of pleasurable euphoria rather than pain. As for the mathematics, I've lost count of the number of times I've ended up regretting those bumps to the head. All in all then, I'm inclined to trust intuition and stay as far away from anything hard as I can. A philosopher I clearly am not.
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