Is that handaxe Windows-compatible? The concept of “range of convenience”

By Gordon Rugg

A “Useful concept for the day” article

This is a replica handaxe that I made in my archaeology days. It’s turned out to be invaluable as a demonstration of assorted useful concepts, though I didn’t expect that when I made it.


What would your response be if someone asked you whether that handaxe is Windows-compatible? You’d probably be surprised by the question, because it’s meaningless. As for explaining why it’s meaningless, though, that’s not so immediately obvious.

This is where range of convenience comes in. It’s from George Kelley’s approach to psychology, namely Personal Construct Theory (PCT). It dates from the 1950s, but still has a strong following today because it offers a clean, systematic, rigorous way of modeling how people think. PCT has a rich, well-developed set of concepts for handling language and categorisation and ideas. Range of convenience is one of those concepts.

In brief, PCT argues that any word can only be meaningfully applied within a particular range of contexts, i.e. the range of convenience. Sometimes that range is narrow; for instance, the concept of Windows-compatible can only be used meaningfully when applied to computer equipment. Sometimes the range is broad; for instance, the adjective good can be applied to a huge range of things.

Some concepts have sharply-defined ranges of convenience, such as Windows-compatible. In general, either an item can definitely be categorised in terms of Windows compatibility, or it definitely can’t.

Other concepts, though, have a much more fuzzy boundary to their range of convenience, and that’s where problems can arise.

Some examples of disagreement about range of convenience that often lead to strong feelings of bafflement and/or rage:

  • The concept of wave and particle, if applied to electrons in physics
  • The concept of customer as opposed to patient or student in public policy
  • The responses that you have to choose between in almost any amateur questionnaire

Range of convenience is a useful concept, and it helps make sense of a lot of things that you know to be wrong, but without being able to put your finger on quite why you’re sure they’re wrong. Other useful concepts will follow in later posts.


Bannister & Fransella’s book Inquiring Man is a good introduction to Personal Construct theory; it’s very readable, short and clear:

Kelley’s book about Personal Construct Theory is clear and fascinating, but a book that you can’t easily read at one sitting, because there’s so much in it that you need to think through:

As a counterpoint, for anyone who is particularly interested in this topic, Osgood et al’s book on Semantic Differential includes an article famously asking whether a boulder is sweet or sour, and claiming to have found the answer, by extending concepts far, far outside their range of convenience:


9 thoughts on “Is that handaxe Windows-compatible? The concept of “range of convenience”

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