I must apologize for not being up on all your arguments in this vein, and I would not ask you to repeat them here. But my question was what is your estimate of the *probability* (a rough guess, of course, if you feel it possible) that CO2 might be a climate factor, not your opinion of the majority likelihood. The latter is already clear.

OK, this is a constructive issue toward reaching consensus. But note that you must also consider a criteria in the presence of solar cycle strengthening or staying the same, or else you are saying you cannot be convinced unless the Sun does something particular. You would be hamstrung to reach a conclusion half the time if the Sun's influence was actually of minimal importance.
Yes, and what I am wondering is, what is the probability that the uncertainties in the analysis could result in the true answer being only 1/3, or 1/6? You see, when one is using science to make policy, it is not enough to cite the majority likelihood. That would be like going to the surgeon and being told that "2/3 of the time the surgery we are proposing will be beneficial to you, so you should have it". Would you go to such a doctor? It depends on the price of being wrong, and that's not a part of any internally scientific calculation.
We can all agree it is frustratingly hard to use science to set policy when the science is in its infancy. Under those circumstances, the greatest strength of science, it's own tolerance for being wrong, becomes its greatest weakness. To me, the fact that CO2 level rise is caused by human intervention, and the fact that it has a potential mechanism for climate change even if unproven, is worthy of attention. What it does is to give us a good reason to sit down and actually come up with a worldwide fossil-fuel energy policy, which we're going to need anyway as fossil fuels become less abundant, although that's equally much an issue of greed versus fairness. Your claim that this is a purely scientific question is an internally inconsistent position, because science in its purest form has no rules for interfacing with public policy. The AGW debate is inherently something a little different from science, because we're not allowed to be wrong here, if one cares about stewardship. It is much closer to the relationship that a doctor has with his/her patient, and we do well to remember their highest mission: do no harm.