I'd ask what constitutes a particle - an atom? any molecule? -- but I already know that you'll say that all mater is waves of nothing so I won't bother.
I do it all the time in my GlaStar with a GPS.
First of all, I never said that an object could not pass through a certain position at a certain time.
But just for fun, no matter how slow of a near-stall you're flying your GlaStar, your gps still takes time to measure velocity. And when it gives you a position and a velocity reading, they will be from slightly different times. And besides, by the time the position is displayed on your gps, you're not in that position anymore anyway.
As far as position and velocity being contradictory, will you do a little experiment for me? Drive down a road at a constant velocity, say 50 mph and when you pass a mile marker, note your time, location and speed. You have just determined position and velocity at the same time, they are not contradictory : ) in the macro world anyway.
I realize it's not polite to quote one's self but I'm going to anyway. What I said was "So to say that something has a position and a velocity at the same time (without mentioning a timeframe) is contradictory."
But just for fun, my speedometer takes time to measure velocity, and it averages the velocity over a second or so period. (Longer in the winter. or above 60MPH.) Furthermore, the reason I need a speedometer is because I have no way to control my speed accurately otherwise, so I cannot just go 50mph except by what my speedometer says. So considering that my speed varies some, but even if I keep my 1-second average right at 50 even, and I note the time I pass through a certain position, I still won't know what my exact speed was as I passed that point because all I know is that the velocity reading will be an average for the second near when I passed the marker - but I won't know exactly where I was when I was actually going at the average speed.
And besides, if something is moving in relation to a certain reference, it doesn't have "a" position - it passes through an infinite number of positions every second.
So how are particles any different? I know that light and radiowaves travel at a predictable velocity. The waves coming from the GPS satellite to your GPS receiver have a path and pass through certain positions at certain times just like a fast moving car would. Electrons moving towards the face of a cathode ray tube move at a velocity controlled by the electric field which accelerated them, and they take time to reach the phosphor screen, do they not?
-Jesse
I think you are confused by Zeno's paradox : ) Let me give you a quote that you might find interesting.
"… Zeno was born in the Greek colony of Elea in Southern Italy in the fifth century BC. He travelled widely for many years and then returned to his birthplace only to be tortured to death after being implicated in a plot to assassinate the city’s tyrant Nearchus. He appears to have been a resilient character: he is said to have bitten off his tongue and spat it at the tyrant during torture. However, it is for his activities during happier days that he is chiefly remembered; particularly a series of paradoxes set in the form of short fables. The most famous concerns a race between Achilles (fleetest of foot of all mortals) and a tortoise. Being far slower than Achilles the tortoise is given a head start of say ten metres. But once the race is off Achilles easily reaches the tortoise’s starting position with a few lengthy bounds. But by now the tortoise has moved on. Achilles leaps after the tortoise but on reaching its last position the tortoise has again advanced by some tiny amount. Achilles again advances but each time Achilles moves to close the gap, the gap is widened. Achilles appears to be unable to ever reach the tortoise (or even to move at all) because to do so he must advance through an infinity of ever decreasing distances.
Zeno knew of course that motion was possible and Achilles would catch up with the tortoise. His paradoxes were to illustrate that something must be wrong about our simplistic notion of time and motion. It took two millennia of mathematical head scratching to solve Zeno’s paradox by demonstrating that an infinite sum can add up to a finite number. However, the paradox lives on in the quantum Zeno effect and the inverse quantum Zeno effect, which describe how a quantum system can be manipulated by measurement. "
Does that help?
So how are particles any different? I know that light and radiowaves travel at a predictable velocity. The waves coming from the GPS satellite to your GPS receiver have a path and pass through certain positions at certain times just like a fast moving car would. Electrons moving towards the face of a cathode ray tube move at a velocity controlled by the electric field which accelerated them, and they take time to reach the phosphor screen, do they not?
Yes, that is what is nice about the speed of light. For all practical purposes it is a constant. Everything else is a variable.