WHAT KINDS OF REASONING ARE THERE? 99While generalised and specific reasoning both depend on classifications of
individual cases in relation to general categories, analogies depend on comparison
and consistency between equally specific or equally general cases. First of all, good
analogies that do not directly involve values are formed through comparing different
things on the basis of consistency of knowledge. That is, we look around for known
cases that are similar to the unknown case, so that we are better able to predict what
we will find out. For example, if we knew that large oil spills at sea destroy the salt-
water environment, we might also predict that similar spills in a freshwater lake
would have a similarly destructive impact. Such analogies depend on the extent to
which we are sure that the world is a consistent place, and that it is very unlikely we
will find radical differences between cases similar in many respects.
Second, good analogies that involve values are formed through comparing
different things on the basis of consistency of action or belief That is, we can use
known cases that have known types of action or belief associated with them and
that are similar to the unknown case to thereby conclude that similar actions or
beliefs can be expected in those cases. Such analogies depend on the assumption
that the world ought to be a consistent place and, to the extent that we can control
what we do in the world, that we should always try to do the same things in similar
situations. For example, we would think it most unreasonable if, of three cars
parked illegally, only ours was given a parking ticket: such rules need to be applied
consistently and we expect that they will be.
Reasoning from terms
The final type of reasoning is less common but equally important. Some claims, as
we have seen, establish the definition of a particular word or phrase. Often we need
to give reasons for our definitions, either because there is some widespread doubt
about them or because we are trying to establish a particular meaning in a given
context. Here is an example:
In a true democracy, all power rests with the people; constitutionally
speaking, in a monarchy some power theoretically resides with the
monarch. Hence, a monarchy is not democratic.
Now, generally speaking, many monarchies (such as Australia) are democratic;
however, this argument establishes that, in a particular context (constitutional
theory), monarchies must be defined as undemocratic. While this definition may
seem unusual and even irrelevant to daily life in countries such as Australia, it does
have some utility within that limited context nevertheless. We tend to find that, by
its nature, definitional reasoning is deductive.
Exercise 7.1
Write arguments or explanations using each of the types of reasoning just
discussed. You should write these examples in the analytical structure format