Wednesday, December 17, 2008

Evolution and me: a personal story (part 7)

Part 7: So . . . is evolution scientific?

Creationists are right: experimentation and observation are important aspects of science, but this is not the whole story. The process of developing ideas (known as hypotheses), making risky predications based on those hypotheses, and then testing these against physical observations, is what forms the foundation of science. This process, called hypothesis testing, is an integral part of the scientific method (see here, here and here). I find it quite strange that in all the creationist and apologetic books I have in my collection, not one of them mention hypothesis testing when discussing science.

Biological evolution, or the idea of common decent, is scientific because we can test it by making risky predictions about what patterns we should expect to observe in the natural world (i.e., in DNA, in the fossil record, in the anatomy of living animals, etc) if evolution were true. We can also, in principle, falsify evolution by thinking about what observations we would not expect to make if evolution was true.

Although an idea can be scientifically valid, this does not mean that it is a scientific fact. Many scientific ideas have failed testing by continuously disagreeing with physical observations. I have argued that evolution is scientific, but I will also argue in the following posts that evolution has been positively confirmed by such a wealth of data that it can be safely regarded as a scientific fact as per Stephen Jay Gould's definition.

But before I move on, I want to first list my sources. Most of the information that will inform these posts originates from the website TalkOrigins, in particular Douglas Theobald's 29 Evidences for Macroevolution. This paper is quite extensive, running to almost 270 pages, so if you are keen to read it in full you can download the PDF version here. Alternatively, for something less complex, you can visit the excellent site Understanding Evolution (thanks to Lui for bringing this to my attention). I will also draw on various books I've read over the years and will reference these in specific posts.

For those of you who want to read argument against my position, take a look at Answers in Genesis and TrueOrigins. In particular you can download a critique of 29 Evidences for Macroevolution here.

Finally, I want to stress the following: I’m not a philosopher, scientist, or biologist, so if you are an academic working in science, creationism, or evolution and you feel I've misrepresented your field of study, please let me know in the comments section, at least for the benefit of other readers. Everything I write on this blog is open to correction, and I really appreciate those who bring my mistakes to my attention. And I also welcome, and hope for, healthy and respectful debate in the next couple of posts.

Now that I have outlined my story of how I came to believe in biological evolution, and provided a brief outline of what science is, I will now jump straight into the specific evidences that convinced me.

And the first revolves around the question of why we struggle to keep insects off our crops . . .

Next post: Observing is believing?
Return to the table of contents for 'Evolution and Me'

6 comments:

Anonymous said...

Kevin,

Thanks for providing all this info (though I'm not yet able to read it all at the moment). I was wondering-- as someone who believes in macroevolution, what were your thoughts about the critique of the "29 Evidences" article? Any good points?

Lui said...

Good stuff Kevin, can't wait.

I've read 29 Evidence but am yet to red the critique of it. There is also a reply to the critique.

Anyway, I look forward to the next installment.

CyberKitten said...

I'm also looking forward to any future debate.

But to answer the original question: So . . . is evolution scientific?

Yes, it is.

Anonymous said...

Hey Kevin,

Good info, but I wanted to run a question by you. You commented that "Many scientific ideas have failed testing by continuously disagreeing with physical observations." To what degree do you feel an idea needs to "fail" at hypothesis testing before it is no longer a valid idea? Some people might assert that one "failure" is all it takes to discredit a scientific theory (or at least significantly modify it); others might assert it takes many failures before an idea should be discarded or altered. I realize there's no definitive opinion on the matter, but I'm curious to know your thoughts.

phil

Kevin Parry said...

Hi Phil

Apologies for only responding now, but both Cori and I were away on holiday, and we didn’t have much access to the internet.

You ask two very interesting questions. Don’t know if my answers will suffice, but here goes.

Phil wrote
what were your thoughts about the critique of the "29 Evidences" article? Any good points?

To be honest, I haven’t started reading the critique in earnest, although I’ve have started with the first few pages. As I post up my remaining articles, I will also work through the critique, and will let you know if any thoughts.

Phil wrote
To what degree do you feel an idea needs to "fail" at hypothesis testing before it is no longer a valid idea? Some people might assert that one "failure" is all it takes to discredit a scientific theory (or at least significantly modify it); others might assert it takes many failures before an idea should be discarded or altered

Excellent question! I will have to do more reading on this, but from what I’ve seen so far I think you are right in saying that there is no definite opinion on this. My own view is that one should not discredit (or even credit) a scientific idea on the result of one single piece of evidence or experiment. The reason for this is that any experiment is prone to some sort of error (e.g., errors caused by faulty equipment or bad experimental design, etc). A single piece of evidence can also be mistakenly interpreted, and all scientists have biases that might negatively influence their interpretation of results. There is also the chance, even if an experiment is done well, that it will provide erroneous results. So I wouldn’t throw out an entire theory, or accept a bran new idea, on one piece of evidence alone.

But these errors and biases are mitigated if the experiment is done over and over again. If many different scientists from around world, conducting different types of experiments and collecting different types of evidence, generally come to the same conclusions on a specific theory, then I think it is safe to provincially accept that theory until another mass of evidence is collected that says otherwise.

I know many scientists didn’t immediately accept Arthur Eddington’s result, as this, at the time, was the only result available. They were wise not to (despite the general media frenzy over the event). But the fact that this result has now been confirmed many times over by many different scientists using different types of equipment, I think it is safe to provincially accept that Einstein’s theory of general relatively stands as an accurate description of how the universe works.

So I don’t think there is an objective line when we can accept of reject a theory or idea because of evidence, but I think it is safe to accept an idea that has been generally confirmed by a mass of experimentation and evidence, not from a single result.

Anonymous said...

Thanks for the great response, Kevin. I think we agree that there is an element of subjectivity when trying to determine when enough evidence exists to convince someone of something. It also brings up the question: At what point has a consensus view been appropriately challenged enough that it is reasonably acceptable to adopt an alternate view? Again, there is probably much bias and subjectivity here, and I would guess, evidences are often interpreted in light of what one wants to believe or already believes.

Hope you and Cori enjoyed the holiday and are well settled back at home now!

phil