<Snipped quote by Nimda>
By that logic, I didn't kill three hundred people. Therefore I couldn't.
You couldn't have in the past. Whether you could or not in the future remains to be seen, but once it has passed, we will see whether you truly could or not.
*Begins to walk around*
You see, no action we take is truly our own, but is a direct result of the inevitable; there isn't a free will, but instead the tricks of time and space causing us to believe we affect our own actions. The future will happen whether we like it or not, and no matter what we change now, that change has already been accounted for in the unavoidable.
*Steps closer to you*
But whether we know the future or not, it is certain. You couldn't, and neither could I.