(June 17, 2015 at 1:10 pm)robvalue Wrote: It doesn't cause it, but it does assure it will happen, if it is actual 100% knowledge. I would say we don't have any such knowledge about anything. We have predictions. You don't know about a full moon, you have a projected probability
You can be assured that there will be a full moon on 1 July 2015. But so what? The assurance and the cause are not the same thing. Knowledge of that fact does not compel that event to occur.
When an honest person promises you something, you may be assured of the person keeping the promise. But the assurance does not cause the person to act.
Predicting the future, and causing it to be that way, are two completely different things.
I have decided that I am going to drink, as long as I live. You can count on that being true; I do not care if, in the future, a doctor tells me that it will kill me. I will give up wine when they pry my corkscrew from my cold, dead fingers. Does that mean that in the future, I lack free will, because I have made such a decision, and am committed to it?
(Not that it matters for the discussion, but I do not drink every day, and a typical day of drinking involves sharing one bottle of wine with my wife. So a typical day will involve me drinking about 3 glasses of wine, not a dramatic amount that is generally unhealthy. But if it became unhealthy for me in particular, I would not stop. I enjoy it, and a life without enjoyment is not worth living.)
I suppose, though, that the better approach in all of this would have been to demand an exact definition of "free will" that is supposedly incompatible with knowing the future, but it really seems pretty much irrelevant to any common notion of the expression. One may, of course, deny that there is such a thing as "free will" at all, and depending on the chosen definition, that might be the most sensible course to take. Of course, that will be irrelevant to other definitions that people use.
"A wise man ... proportions his belief to the evidence."
— David Hume, An Enquiry Concerning Human Understanding, Section X, Part I.
