Wikipedia, I have discovered, has the following entry for category mistake, which attributes the phrase to Gilbert Ryle, The Concept of Mind:

'A category mistake, or category error is a semantic or ontological error by which a property is ascribed to a thing that could not possibly have that property. For example, the statement "the business of the book sleeps eternally" is syntactically correct, but it is meaningless or nonsense or, at the very most, metaphorical, because it incorrectly ascribes the property, sleeps eternally, to business, and incorrectly ascribes the property, business, to the token, the book.

The term "category mistake" was introduced by Gilbert Ryle in his book The Concept of Mind to remove what he argued to be a confusion over the nature of mind born from Cartesian metaphysics. It was alleged to be a mistake to treat the mind as an object made of an immaterial substance because predications of substance are not meaningful for a collection of dispositions and capacities.'

(http://en.wikipedia.org/wiki/Category_mistake)

I uncovered this as one of the results of a Google search on 23.10.2006 for 'category mistake', which also threw up a number of other noteworthy items. One was:

http://categorymistake.com/blog/category-mistake/

While it was initially exciting to discover an entire website actually devoted to the concept, the number of entries turned out to be disappointingly few.

The privately maintained site at:

http://www.philosophypages.com/dy/c.htm

had some useful background definitions, though they didn't really shed any new light. It did, however, concur in attributing the idea of a category mistake to Ryle (as does this post http://www.philo.at/phlo/199806/msg00048.html which notes Mautner's Dictionary of Philosophy as a source for the attribution), and underlined that in order to give any real meaning to the notion of a 'category mistake', it is important to be able to say what is entailed in the notion of a category itself:

'category {Gk. katęgoria}

Predicate; hence, a fundamental class of things in our conceptual framework. In Aristotle's logic specifically, the categories are the ten general modes of being (substance, quantity, quality, relation, place, time, position, possession, doing, and undergoing) by reference to which any individual thing may be described. Following the lead of stoic thought, medieval logicians commonly employed only the first four of these ten, but allowed for additional, syncategorematic terms that belonged to none of them. Kant employed a schematized table of a dozen categories as the basis for our understanding of the phenomenal realm. Gilbert Ryle used the term much more broadly, warning of the category mistakes that occur when we fail to respect the unique features of kinds of things.'

An important example of the use of the term in public discourse that should have been recorded here was that by the Archbishop of Canterbury on 21 March 2006, when he said:

"I think creationism is, in a sense, a kind of category mistake, as if the Bible were a theory like other theories.

"Whatever the biblical account of creation is, it's not a theory alongside theories. It's not as if the writer of Genesis or whatever sat down and said: 'Well, how am I going to explain all this... I know: in the beginning God created the heavens and the earth'.

"So if creationism is presented as a stark alternative theory alongside other theories I think there's just been a jarring of categories. It's not what it's about."

I was reminded of the A of C's remarks by a post on (http://www.jacobsen.no/anders/blog/archives/2006/03/21/), so clearly I wasn't the only one who noticed.

This fits nicely with the comments in the last couple of entries.

But there is another example that is worth recording for its assertion of a distinction between historical and moral understandings of action and its claim that the confusion between them also amounts to a category mistake: see the note on 'Historical explanation and moral justification' by Gene Callahan which was inspired by the response to the attack on America in September 2001 (http://www.lewrockwell.com/callahan/callahan60.html)

It seems contemporary uses of the phrase 'category mistake' span a wide variety of fields indeed; science and religion, science and art, history and morals, thought and action. It is all a far cry from Ryle's original usage of it in relation to the Cartesian approach to the mind-body 'problem'.