In logic, statements that are explicitly supposed as
There are three things to be
noted about assumptions:
1. One needs a term like this, whether premiss,
or - like here - assumption, simply because one does make assumptions, and
especially in the course of arguments.
2. Assumptions are supposed to be true, but need not be
believed to be
true. One reason is that one may make an assumption in order to refute it by a
reductio ad absurdum; another
reason is that one may need to make an assumption to
explain something, without knowing that the
assumption is true; a third reason is that one may for the moment simply make
assumptions to see where the argument leads.
3. There is a general problem of assumptions, which may be stated as
follows: What assumptions does one really make to
explain something? (See:
Presupposition) This sort of question is
especially important in philosophy,
epistemology, and it is often not at all easy to recognize and state
clearly what it is that one in fact assumes as a matter of course. An example
outside the fields mentioned is the grammar of one's natural language.