bill d. - extremely clear, lucid and articulate. However, there are usually criteria for how one should opt. Of course one can opt for anything (that is the nature of free choice). However, there are legal, ethical, mathematical discussions of how to make a responsible choice. There are tomes and tomes written on this. What if your doctor were to pull off such a line, of saying, since I'm not certain I won't take that last reasoning step? He could choose to do so - however, there can be questions as to what he should have thought "probable" and how he should have chosen a step "responsibly". This actually has come up in legal cases - as well as discussed in business ethics, and in mathematics.