Q&A: Has Physics Eliminated Causality?
Has Physics Eliminated Causality?
Question
Hello.
Can one say, according to physics, that the elevator is going down, or alternatively that the building is going up? Does everything depend on the frame of reference?
Can one say that the moving car is approaching the car parked in the parking lot with the handbrake on? And can one also say that the car with the handbrake on is traveling toward the sputtering car with smoke coming out of its exhaust?
That seems crooked and contrary to common sense to me. Is that really what physics says, or is it just a trick for calculation and easier problem-solving? And after all, how does the driver in car A cause the parked car to move if he presses his own gas pedal? How do I move the wall when I “walk” toward it? And why doesn’t this amount to abolishing the principle of causality??
Answer
Relative motion is a matter of definition. In physics, motion is defined relative to a frame of reference. In everyday life, motion is defined differently (because a particular frame of reference is assumed).
There is no abolition of the principle of causality, because without pressing the gas pedal, the world would not move backward relative to my car.