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Re: CAUSATION IN PHYSICS



Yes, that is one way of defining cause and effect. However consider. To accelerate a block you must push it. or To push a block you must accelerate it. The latter construction does not make sense. This could be a limitation imposed by language which has constructs for causality, and also for unrelatedness, but does not have a good construct for correlated things which are not causally related in time. Do we really know that acceleration and Force are "exactly" simultaneous?

The problem with beginning students is that they do not seem to understand that to exert a force there must be a connection between 2 objects. At the most basic level they must see that hands must touch balls to push them. Many students believe that pitchers make baseballs curve by doing something after the ball has left the hand. (spooky action at a distance?) The students must connect the events in a series. Touching produces forces, and the result is a change in motion when unbalanced. They must first treat the event in a concrete fashion. Then they have to begin to understand that acceleration implies unbalanced forces. So the fact that mathematically there is not way to separate cause and effect, does not in any way alter the fact that humans tend to think of forces as causes and acceleration as an effect. This sort of reasoning permeates most explanations of physical effects. Rockets go up because the exhaust gasses are expelled downward. Notice that this sort of reaction and action sequenc
seems natural, but it is not actually NTN3. NTN3 only talks about the forces, without a cause implied. Again "The car moved because the boys pushed it" is natural, while "The boys pushed the car because it moved" has a very different implication (perhaps they were trying to stop it). "The boys pushed the car and the car moved" again has different possible implications.

Another important idea to consider is that an equation is an abstraction with the context removed, while a description contains much more information. Formal logic has distinct limitations. Often logical deductions can made on the basis of implied context rather than on the strictly stated facts.

Maybe it would be better to say that treating acceleration as an effect and force as a cause is just a good working model to help students understand what is happening. In a sense I suppose this is metaphysics, but if it helps students make sense of ideas, then it is useful.

Is explaining acceleration as effect and force as cause correct? I think this actually unanswerable. It is just useful!

John M. Clement
St. Pius X HS, Houston, TX

Subject: Re: CAUSATION IN PHYSICS


Do not cause and effect form a temporal sequence.
If cause and effect are simultaneous naming one as
cause and the other as effect does not make sense.

regards,

sarma.