Evaluating competing theories(*)

[David Kerridge <dfk@rsc.co.uk>]

Dan Swart asks:

>Can a management theory have examples that disprove it,
> and still be useful?

This  applies to any theory, not just in management. But it is
true of  theories in the sense of "rules that predict the future",
not necessarily of theories in any other sense, such as explanation.

If a theory says that something will *never* happen, and
you find an exception, then your original statement of the
theory is wrong: but you can often make the theory *more*
useful. You now know more about when to rely on it, and
so it is safer to use it. Newton's Law of Gravity is "wrong"
in the sense that we now know of deviations from it under
extreme circumstances. But restate it as: "Under the circumstances
in which you are likely to use it, such as building bridges,
or sending rockets to the moon, Newton's Law predicts
as accurately as you need for that purpose".

So the exceptions destroyed Newton's theory as an explanation
of why apples fall, but improved the theory as a way of predicting
*how* apples fall.

And then there are laws, best described as statistical laws,
such as: "If you improve training you will usually get better
 results". As stated, it is a pretty crude law: but by finding
exceptions, you help to refine what is meant by "better",
 and "usually". I take it that this is what Dan Swart
 means by a "Rule of Thumb".

The simplest theories to use are those to which there are no
known exceptions. We call these "Fundamental Scientific
Laws". But many of our everyday actions are based on
"rules of thumb". One such is "Reduce the number of
Suppliers". There are exceptions: see the appendix to the
Second edition of "The New Economics". By studying these
exceptions we gain a greater understanding of the theory.

Best wishes

David

dfk@rsc.co.uk
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