 Instead, by virtue of the principle of pre-established harmony, each monad follows a pre-programmed set of "instructions" peculiar to itself, so that a monad "knows" what to do at each moment.By virtue of these intrinsic instructions, each monad is like a little mirror of the universe.Monads need not be "small"; e.g., each human being constitutes a monad, in which case free will is problematic.