rce's definition of a sign and use of logic might,
    or might not, be related to any of the wide variety of
    inquiry that produced great discoveries in physics.

Yes, it is a little bit like reading Galois on Group Theory.
If you have a hundred years or so to get a grasp on what
a group is, then you can read his work and realize that
everything he says is perfectly apt.  Sadly, we are
not to that point yet, where the Theory of Signs
is a standard part of the undergrad curriculum.

My own advice would b