"Understand".

Christ, I don't understand "understand".

Scotty, I don't set traps. I just make mistakes, sometimes. Say what you think. Either I'm starting to like your style, or your style is mellowing, but that's Relativity for you.

Since this is already verging on the mathematico-philosophical, here's my final observation. You can't be sure of anything. I had this adolescent dream of finding out how to calculate anything. One by one all the golden promises evaporated. Every calculation is a guess. Even the math we use is just a set of arbitrary rules we made up that seem to describe certain aspects of the real world, sometimes, with the following exceptions....
Engineering turned out to be gross overestimates of (you name it) built into the design, and called a safety factor. "Pure" science turned out to be politics and intellectual snobbery. Many of my generation became obsessed with saving the world, and are still at it today. I have all I can do to save my little part, and I'm not "sure" of anything I'm doing...

You make the best guess you can on the best data you can get, and you keep a bolt hole handy, and trust that hunch. I love "The Prince": "God we thank you for your gift of free will and thus that share of the glory that is ours"