Well in that scenario, the only way your speed would be constant (assuming a constant angle on the hill) is if your engine thrust was constant. So "pumping" the

Well in that scenario, the only way your speed would be constant (assuming a constant angle on the hill) is if your engine thrust was constant. So "pumping" the gas just achieves a constant thrust. So your speed stays the same and the thrust stays the same. So there is perfect correlation and causation (by some definition of causation). But more to the point, there isn't a good definition of causation. If you use the "but for A, B would not occur" there are problems. Other definitions also have problems. This is a deep epistemological problem and I think not as simple as it may seem.