The Third Grave Error

Newton’s third law of motion states:

When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

If this were the case there would not be any motion since any increase in force (aka tendency to move another object) would automatically be resisted by the second body as defined in Newton’s 3rd Law. It would be more apt to call Newton’s 3rd law as the law of immotion.

I’ve always wondered how Newton, or anyone for that matter, arrived at this description of physical reality, for clearly he seems to be describing a state which is the opposite of his first two laws that are laws of motion.

At first sight one suspects Newton is describing inertia but this is illogical because once inertia is overcome motion ensues and the 3rd Law becomes irrelevant.

So I wonder if Newton was guilty of the logical fallacy of arguing the consequent, that static objects are not moving because one is stopping the other. Or that two bodies attracted to each other cease moving when they touch because of the 3rd Law.

It seems that if bodies move because of some innate attractive tendency in the volume of matter which forms a shape or body, and when this body moves towards and stops moving once contact is made with a second body possessing the same innate qualities of attraction, then this is because of the 3rd Law.

Which seems to be a refutation of the theory of gravitational accretion, in that once two bodies make contact with each other, no further motion become possible.

Update: And the bodies need not even be in contact if one reads the Law explicitly, merely that if gravity of one body exerts a force on a second body, then it will be equally resisted by the other body. I wonder if Newton understood what he was describing.

Update 1: Reading Wikipedia’s entry on this topic, it is stated that Newton’s Laws apply to point masses. These are non-physical objects and in fact are not physical objects at all but locations possessing a force attributable to mass.  Obi-wan’s Force is more believable.

About Louis Hissink

Retired diamond exploration geologist. I spent my professional life looking for mineral deposits, found some, and also located a number of kimberlites in NSW and Western Australia. Exploration geology is the closest one can get to practicing the scientific method, mineral exploration always being concerned with finding anomalous geophysical or geochemical data, framing a model and explanation for the anomaly and then testing it with drilling or excavation. All scientific theories are ultimately false since they invariably involved explaining something with incomplete extant knowledge. Since no one is omniscient or knows everything, so too scientific theories which are solely limited to existing knowledge. Because the future always yields new data, scientific theories must change to be compatible with the new data. Thus a true scientist is never in love with any particular theory, always knowing that when the facts change, so too must he/she change their minds.
This entry was posted in Hare-brained theories, Philosophy, Science and tagged , , . Bookmark the permalink.

One Response to The Third Grave Error

  1. Thx1138 says:

    A disturbance in the force, there is.


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