Newton's 3rd Law
loud cracking sound you hear when the hero punches the villain in the jaw
is the sound of finger bones breaking. Jaw bones are stronger
than finger bones."
said by a movie critic
"To every action there is always opposed an equal reaction; or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts."said by Isaac Newton
For every action, there's an equal and opposite reaction.
This law is not about cause and effect.
It is not about "what happens."
This law observes that forces are interactions between two objects.
The forces are equal because they are the same thing. The are in opposite directions because they are acting upon the two different objects.
The two forces are an inseverable pair.
This law, the last of the three, is the simplest. It's also the most subtle.
It gave Newton some concern. Remember, he was examining the behavior of the moon orbiting the Earth and the Earth orbiting the sun. Here, the forces are gravity. They act over enormous distances.
How can that be? Is there something that "carries," that "transmits," that force? Three centuries later, we still find we are peering past the edges of human comprehension here. We speak of "exchange particles" as part of the interaction: photons in the case of the force due to charge, gravitons in the case of the force due to gravity, plus a couple of other "-ons" for a couple of other forces that hold things together deep inside the atom.
This means that the light by which we see is "carrying" the forces between our eyes and what we are looking at. It's a force that's there because the electrons and protons in our eyes and in the object have "charge" and push and pull on each other.
Very simple. Very subtle.
Movie lore has heros dominating villains by the force of the fist. Villains are identified by simplistic, superficial criteria. Heros are usually identified by the simplest, most superficial criterion of all: they is us! Mutual reciprocity is "abstract, ivory towered and quite out of touch with the real world" in this culture's lore. Several years ago we saw an epidemic of broken fingers when several professional athletes saw fit to try to live up to the movie hero physics.
You can't fool Mother Nature! Rationality works.
Every cause has an effect and every effect has some cause(s).
DEVELOP THE NEEDED
PERCEPTION, WE DO