Steve Shaw, you just said a magic word: "counter-intuitive".

We all, I think, intuitively feel that any event has some cause. That's part of why the Big Bang is so hard for people to swallow. And the idea that the Judaeo-Christian god was not caused or created, but existed forever, as an attempted escape from the First-Cause argument. But we (or at least I) know that many, many, many intuitive convictions or judgments turn out to have no basis, once investigated.

Many, many scientific studies are ridiculed because they inquire into beliefs or relations that almost all of humanity have historically found intuitively true: "They have to have an experiment to study THAT? Everybody knows that!" and if their findings are contrary to the intuitive opinions the findings tend to be attacked.

Steve, I think you are in essence saying that, "If we could just investigate and investigate the origins of mutations, I believe that somewhere back there we'd find a cause, because I find universal causation intuitively powerful."

And so do I; I'm more comfortable intellectually with the idea of universal causation. I suppose everyone is, at first blush.

But to say that a stressor such as radiation, asbestos fiber, or some chemical makes cellular-level (and intracellular) change statistically more common doesn't quite get to the level of causation of a particular change. And WHICH specific change in many cases appears not to be "caused" by the stressor impinging; the result is "caused" all right, I think, but by such a multitude of environmental and cellular facts as to ultimately unpredictable, thus random. We are talking about "faith" here, faith in causation, which I share; and also adopting or rejecting one or another meaning of "random" in support of one or another intuitive judgment

You close with "at least I'm not being counter-intuitive". That may be just the problem, on both sides of this particular corner of the discussion.

Dave Oesterreich