Here's a reasonably clear explanation:

"Begging the question" is a form of logical fallacy in which a statement or claim is assumed to be true without evidence other than the statement or claim itself. When one begs the question, the initial assumption of a statement is treated as already proven without any logic to show why the statement is true in the first place.

A simple example would be "I think he is unattractive because he is ugly." The adjective "ugly" does not explain why the subject is "unattractive" -- they virtually amount to the same subjective meaning, and the proof is merely a restatement of the premise. The sentence has begged the question.

It may be that it's an archaic use of begged? Because that's part of the problem, I think - the name for the fallacy makes no obvious sense itself. The misuse seems more rational.

Huh! I had never thought about that particular phrase, and that's interesting. Thank you, brenda!

I think actionable has a precise legal meaning, not sure I know of it in other contexts.

I think that "beg the question" is a weird translation from a Latin phrase that, in a more modern translation, would make more sense. (I can't remember what the Latin is, though.)

(Which begs the question: why are we so keen to retain archaic meanings when the new ones are so useful?)

This is a job for erinaceous!

This is a job for erinaceous!

She's no prescriptivist.

She is, however, a Northern Californian now.

I just used wordnik for the first time to see other uses for the word "actionable." Now that is a useful site!

I have never heard decimate used in the traditional sense

They did it right on Dr. Who, bless them. I first learnt it in the traditional sense, and it was a while before I heard it used conventionally and wrong.

As for the samurai sword--there aren't that many of them around that are that sharp--most would be replicas. I don't know if mine would take that good an edge. My blades that would get that sharp are shorter and are probably ill-suited for swinging at an extremity. More something you'd lodge in someone's clavicle.

I have been idly looking for a sword-sharpener for ages. I thought I'd found one, but he moved out of state. I should have gotten them all done when I had the disposable income, dammit. I just never looked seriously enough. It's not like it's a hard search.

Special K:

why are we so keen to retain archaic meanings when the new ones are so useful?

Decimate ain't one of those. Devastate works just fine. One might not mean decimate often, but when you do, how many other words work as well?

Dear lord, I still seem to be watching 90210. And Melrose Place. Which seems to have a murderer. And a whore. And an art thief. It's total crack, even compared to the original.

I could probably rephrase:

why are we so keen to retain archaic meanings when they are so useless?

I always cringe when people use decimate instead of devastate, but I fully admit that that's just priggishness on my part, because I'm smart enough to have been told the difference at some point. Stephen Fry talked me out of it in a podcast last year.