"For every person who tries to define them, someone else will come along and express different views. Who’s right?"

That comes down to philosophy. That is, whose definition is meaningful, whose definition distuinguishes science from other fields, whose definition captures the essence of what is commonly understood to be science? Answer: my definition. I'll give you a hint, I was taught this definition in high school scinece, and have seen it used constantly since. It is the only definition with any real meaning.

"My concepts of science are strong, and not likely to change."

I think you'll find that they become more 'refined' as this discussion progresses.

Celevia:

"The theory of common descent permits a large number of predictions of new results that would be improbable without evolution."

That doesn't make it falsifiable. If you only have one reasonable theory to explain things then you cannot say that something would be improbable without that theory. Or you can, but it is meaningless, especially in a scientific context.

"Such observations can be regarded as attempts to falsify the theory of common descent."

Not in any rigourous way. A lot of the 'predictions' you give were not made until after the observations ahd been made.
"We conclude that the theory of common descent is an easily-falsifiable..."

For something to be falsifiable in a scientific context, you hae to be able to do a repeatable experiment that would disprove it if it were false.

The main attraction of the theory of evolution is it's infinite flexibility. It makes it an attractive theory, but it also makes it complete unfalsifiable. Even if the fossil record were backwards you could still explain it with evolution. Imagine it were, and the little slugs on the sea floor could talk, you would hear them exclaim "Hallelujah! God (oops I mean evolution) made it so. We are perfectly adapted, the results of billions of years of evolution. Lo! See how we have cast off the rediculous assembly of organs and appendages which our distant ancestors had to make do with"

"For something to be falsifiable in a scientific context, you hae to be able to do a repeatable experiment that would disprove it if it were false."

Hilarious. You are seriously on another planet. What you have described above is *exactly* what has been done countless times for Evolution, over the course of no less than 100 years of testing.

And don't even get me started on your last paragraph. You cant debate evolution if you don't even have the most basic understanding of what the actual theory is.

No it hasn't. What you describe is making a bunch of observations and coming up with an explanation that fits the patterns, then checking again that the patterns you observe still fit the observations. It is not an experiment at all.

http://www.ozpolitic.com/evolution/what-is-experiment.html

freediver - what I described is actually irrelevant, because the theory and debate surrounding Evolution is not confined to this thread on this website, believe it or not. Outside this discussion, there's actually a world of study, past and present, and believe it or not (and this is the last time I'll say it, I promise), the entire scientific community accepts the theory of Evolution and agrees it is entirely falsifiable by any common understanding of the word.

So what we say here is actually pretty fruitless, as this stuff has already been sorted out by the pros a long time ago. Read as: evolution is here to say, regardless of whether you like it or not.

PS: don't bother with the links. Not interested. 100 years of compiled scientific study and evidence vs some dinky website? Even you should be able to see the imbalance there.

"the entire scientific community accepts the theory of Evolution and agrees it is entirely falsifiable by any common understanding of the word"

No they don't. And I am not referring to the common understanding. I am referring to it's meaning within a scientific context. Theory and law have a completely different meaning in common language too.

"So what we say here is actually pretty fruitless, as this stuff has already been sorted out by the pros a long time ago. "

Which is why they call it natural history, not science.

"Read as: evolution is here to say, regardless of whether you like it or not."

I am not trying to make it go away. I am simply pointing out that it is not a scientific theory.

"PS: don't bother with the links. Not interested. 100 years of compiled scientific study and evidence vs some dinky website? Even you should be able to see the imbalance there."

Ah, the old ad hominem again:

http://www.ozpolitic.com/articles/logical-fallacies.html#ad%20hominem

Freedriver, I would have thought that creationists have anxiously spent considerable time claiming that evolution has been falsified.

I also think that the theory of common descent would be quite easy to falsify. It has often been tested, hasn’t it?