My son was taking a class in college on the philosophy of science.
One of the things they talked about was the validity of induction.
The basic idea of induction is to identify a pattern and extrapolate
it forward. Simplified, induction assumes that the way things have been
in the past is the way they will be in the future.
The question is, is induction valid? One simple argument is that it is
reasonable to assume that induction is valid because it's always worked
so far. However this is a circular argument, because it applies the
principle of induction to justify induction. They illustrated this with
an amusing variant.
"Revolutionary induction" is the opposite of induction. It assumes that
the way things have been in the past is *different* from the way they
will be in the future. In other words, it predicts the opposite of our
Revolutionary induction has not worked so far. Therefore it predicts
that it will work in the future.
The point is that the philosophical justification of revolutionary
induction is just as strong as that for induction, as far as this class
of arguments goes. So we have to look elsewhere for a justification of
induction than the fact that it has always worked so far.