You say:
"My final point is rather incidental.  When Galileo invented the
telescope, the professional astronomers of the academic community
refused to look through it, claiming that it was a trick.  When did the
truth change?"
My answer: Truth never changes.  Only our beliefs about what is true change.
 
You say:
"Isaac Newton, in his experiments on the refraction of light, largely
because of the force of his intellect, ignored evidence, which he almost
certainly saw, that light was not a particle, but was actually a wave.
His ideas, arguably the greatest scientific oeuvre of any man in
history, remained undisputed for centuries.  Were they true or false?"
 
My answer: We can never be certain of what is true.  Philosophical Realists are
all Fallibilists in this sense.  My impression is that scientists now believe
that much but not all of what Newton claimed is true.  Light has both particle
and wave aspects but is neither.
 
You say:
"When the ideas finally fell, within a relatively short period of time,
it became clear that there was not one view, but two.  Interestingly
enough, if one was true, the other was false, and visa versa.  Both of
these ideas were equally useful, even though they were mutually
exclusive.  Were they both true?"
My answer: You raise a complex philosophical issue far beyond the scope of this
forum.  In a literal sense almost all scientific theories are false in the sense
that they involve idealized models that are acknowledged to be false in the
literal sense.  The current theoretical "model" of light uses both the wave and
the particle metaphor.  In a sense, both are true and both are false. If you
follow the history of beliefs about the nature of the atom, the plum pudding
model was replaced by Rutherford's planetary model, and this was replaced by
Bohr's model which was replaced by a later Bohr model.  All of the models are
literally false, but each one is believed to be a better approximation of the
truth.  None of them are as false as the phlogiston theory of combustion.
 
You say:
"Most recently in high energy physics, people invented a the a model of
atomic particles, that was consistent with known observations, but
seemed almost absurd.  However, it was intellectually useful.  Over
time, they began to establish, by bits and pieces that it predicted the
existence of things that had never been seen before, and one by one,
they found their missing Quarks.  When was the model true and when was
it false?"
My answer: If the theory is true, it was always true.  We currently believe it
is true.  It was once believed that combustion was explained by Phlogiston.  Do
you believe the phlogiston theory once was true? I have read about Burbaki but
can't discuss the point you raise.  My general point is that your examples don't
support what I call "controversial relativism" i.e. the notion that the truth of
a statement changes with what historical period or what culture one is in.  All
scientific theories using idealized models that are currently accepted are in
some sense literally false.  This is not the same thing as a false theory being
"useful."  One might claim that a belief in witches is "useful" if faith healers
can help some patients by exorcizing demons.  Witches are not an idealized model
of something existing in reality.
 
Eric