To think clearly and to argue well, you need to understand: first,
how to develop a proposition or a case from basic principles;
second, how to test your proposition; and third, how to avoid
using fallacious arguments and how to expose the fallacies used
by others.
DEVELOPING A PROPOSITION
The first rule is to ‘get the facts’. It is the starting point for clear
thinking. The facts must be relevant to the issue under consider-
ation. If comparisons are being made, like must be compared
with like. Trends must be related to an appropriate base date,
and if trends are being compared, the same base should be used.
Treat opinions with caution until they are supported by
evidence. Avoid a superficial analysis of surface data. Dig deep.
Take nothing for granted. Sift the evidence and discard what is
irrelevant.
Your inferences should be derived directly from the facts.
Where possible, the connection between the facts and the conclu-
sion should be shown to be justified on the basis of verifiable and
relevant experience or information on similar relationships
occurring elsewhere.
If, as is likely, more than one inference can be deduced from
the facts, you should test each inference to establish which one
most clearly derives from the evidence as supported by experi-
ence. But it is no good saying ‘it stands to reason’ or ‘it’s common
sense’. You have to produce the evidence which proves that the
inference is reasonable and you have to pin down the vague
concept of common sense to the data and experience upon which
it is based. It was Descartes who wrote: ‘Common sense is the
best distributed commodity in the world, for every man is
convinced that he is well supplied with it.’
TESTING PROPOSITIONS
Susan Stebbing (1959) in Thinking to Some Purposewrote: ‘We are
content to accept without testing any belief that fits in with our
prejudices and whose truth is necessary for the satisfaction of
our desires.’ Clear thinking must try to avoid this trap.
294 How to be an Even Better Manager