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7
The Character of
Natural Laws
We have already studied quite a few different but speci c laws: the law of gravity, the
laws of motion, and the laws of electricity and magnetism. What we will discuss in
this chapter are some overriding principles that most, if not all, laws seem to follow.
This not only tells us something deep about the nature of nature, but also demon-
strates the unity of physics.
7.1 CAUSALITY
The principle of causality is really quite simple. It states:
The cause must always come before the effect.
At this point you are probably thinking to yourself that is pretty trivial. So what’s
the big deal?
Well, because it is so prima ...