Here is the question before you today, ladies and gentlemen: Do our brains calculate, or do they measure with their own methods? I posed myself this question when thinking about subconscious estimation...like when you catch a baseball, you don't know exactly how fast its going, but in under a second your brain calculates about how fast its going, so you can catch it. Now, the question applied to this problem would be: Does your brain actually use the laws of projectile motion, and a certain distance with a certain time, etc, to subconsciously calculate and tell you how and when to catch it? --OR-- Are the laws of projectile motion and velocity, etc actually what your brain uses...or are they jsut ways that we have created to explain how things work..and maybe our brain uses some other method (that probably cannot be mathematically modeled) to figure things like this out? My answer would be that it probably uses some other method, and my reasoning for this is how we learn things. If a quarterback throws to a receiver running the same route over and over, he will become more and more accurate. Assuming your brain's estimation of time and distance does not change, but rather jsut it's estimation (and your arm motion stays consistent in accuracy...any difference is related to brain estimation) of 'where to throw' changes, I do not know of a way this change could be accurately modeled...that is, if it actually used the laws of physics, it would come up with the exact same value every time...but hey, what do I know! THE question is, what do you think?