The problems of politics involve, finally, in addition to questions
of structure and purpose or questions of what is best in
the abstract or in this particular case or in general, questions
of generation, change, and destruction, questions concerning
how a state of any given kind may be initiated and set up, how
it may be continued once established, and how it may be overthrown.
The pursuit of inquiry into efficient causes, which alone
are suited to solve problems of generation, destruction, or preservation,
led Aristotle to his shrewd analysis of revolutions, of
the means by which to foment movements that lead to changes
in a constitution, the devices by which to thwart them, and the
precautions to be taken against them.