Re: Modelling Considered Harmful

In message <4v4mj2-92l.ln1_at_pluto.downsfam.net>, Kenneth Downs <knode.wants.this_at_see.sigblock> writes

None of those precisely match my understanding of a model in this context. I would add:

7. An abstraction of a real-world system against which theories about the real world system can be tested.

>So where is the harm? Well, there is always a problem when you call a car a
>horse, because you risk stuffing hay down the gas pipe and you can really
>scratch the finish with those brushes. Any attempt to advance the theory
>of databases should understand them for what they are, or the theory will
>go off in the wrong direction.

I come across this problem whenever I teach management theories. There are always people who claim that because the models that we use in the theories don't precisely match reality they are valueless. These people usually go on to claim that only real-world experience has any value. Such people, of course, know that academic qualifications have no value because they only teach theory.

I usually try to forestall any such arguments by starting out with a session teaching the theory of theories.

Given:

        Management theories always work.

        Management theories never work.

        Both of the above statements are true.

Discuss!

The problem with people who distrust theories is that they seem to expect theories and models to provide all of the information they require. Theories and models are an aid to good practise, not a substitute for it. Knowing that there are some similarities between cars and horses could be useful. It might lead to the supposition that horses need fuel and avoid a naive horse owner from starving their transport.

Assuming the truth of the wrong similarities ends up with things like the recently repealed British law that required taxi drivers to carry a bale of hay at all times. Luckily the law did not specify the size of the bale.

Models have their uses but good practitioners test their theories against each real-world situation they encounter and reject aspects of the model that don't respond in the expected ways.

-- 
Bernard Peek
London, UK. DBA, Manager, Trainer & Author.