11. Confusion concerns always two ideas.
Confusion making it a difficulty to separate two things that should be
separated, concerns always two ideas; and those most which most approach one another. Whenever, therefore, we
suspect any idea to be confused, we must examine what other it is in danger to be confounded with, or which it
cannot easily be separated from; and that will always be found an idea belonging to another name, and so should
be a different thing, from which yet it is not sufficiently distinct: being either the same with it, or making a part of
it, or at least as properly called by that name as the other it is ranked under; and so keeps not that difference from
that other idea which the different names import.