Moral force and material force do pass into one another; a conflict of
opinion often ends in a fight. Putting it the other way, there is no
material conflict without attendant clash of opinion. Opinion and matter
act and react as do all things else; they come up hand in hand out of
something which is both and neither, but, so far as we can catch sight of
either first on our mental horizon, it is opinion that is the prior of
the two.