Kinds of Claims (Last revised 31 August 2005)
- There are many kinds of utterances: some accomplish
something, some express emotions, some makes claims, and so on.
- "Close the window!"
- "I promise I'll do it."
- "Two is the square root of four."
- Our interest will be with claims. We assume that claims
are expressed by sentences and are either true or false, and
never both, nor ever neither true or false. (There may be
things which are not true or false but which look like claims
-- some people think aesthetic claims are like this -- and
there may be claims which are both true and false -- some
think that "This sentence is false" is like that. We will
assume instead that there are some true or false claims and
will be discussing just these.)
- There are at least four kinds of claims
- Empirical claims
- Logical and mathematical claims
- Methodological and metaphysical claims
- Ethical and aesthetic claims
Kinds of Claims
- Empirical claims describe the natural world, and
refer always to things which can in principle be experienced
by our senses. Also:
- Their truth value can be settled by observation(s)
of some kind.
- They are contingent: they are not necessarily
true. This means that for some empirical claim C
there is some consistent description of the world in
which the claim is false, and another consistent
description of the claim where the claim is true.
- Mathematical and Logical Claims describe the
structure of reason and the pure products of reason. (We will
assume that math and logic are two aspects of the same
enterprise, and not therefore significantly different, and will
therefore use from here forward the term "logic" to refer both
to math and traditional logic.)
- Their truth value can be determined by
using a proof (by reason alone).
- They are necessary: if a logical claim C is true
it must be true (given your other assumptions) and to
deny C is to contradict yourself. (Although for very
complex claims you may not be able to determine what
such a contradiction is.)
- Methodological and metaphysical Claims are usually
stipulations about how we should do something, or are non-empirical
claims about the nature of the world. These kinds of claims
arise because we need to agree on standards; or because we may have
certain questions which cannot be settled by observation and
- Ethical and Aesthetic Claims are logically distinct
from empirical and logical claims because they concern not what
is but rather what should be. Some philosophers believe
these are not really claims, but most people (and most philosophers)
believe that they are. If they are, then there remains little
or no consensus to settle when they are true or false.
We will be concerned mostly with empirical and with logical claims in
this class. We will make many methodological and metaphysical claims,
but not be concerned directly with evaluating them. We will discuss
ethical claims only in passing, to show how importantly they contrast
with empirical and mathematical claims.