# canonical

canonical: [historically, `according to religious law'] adj. The
```   usual or standard state or manner of something.  This word has a
somewhat more technical meaning in mathematics.  Two formulas such
as 9 + x and x + 9 are said to be equivalent because
they mean the same thing, but the second one is in `canonical
form' because it is written in the usual way, with the highest
power of x first.  Usually there are fixed rules you can use
to decide whether something is in canonical form.  The jargon
meaning, a relaxation of the technical meaning, acquired its
prominence in Alonzo Church's work in computation theory and
mathematical logic (see Knights of the Lambda Calculus).
Compare vanilla.

This word has an interesting history.  Non-technical academics do
not use the adjective `canonical' in any of the senses defined
above with any regularity; they do however use the nouns `canon'
and `canonicity' (not **canonicalness or **canonicality). The
`canon' of a given author is the complete body of authentic works
by that author (this usage is familiar to Sherlock Holmes fans as
well as to literary scholars).  `*The* canon' is the body of
works in a given field (e.g., works of literature, or of art, or of
music) deemed worthwhile for students to study and for scholars to
investigate.

The word `canon' derives ultimately from the Greek
`kanon'
(akin to the English `cane') referring to a reed.  Reeds were used
for measurement, and in Latin and later Greek the word `canon'
meant a rule or a standard.  The establishment of a canon of
scriptures within Christianity was meant to define a standard or a
rule for the religion.  The above non-techspeak academic usages
stem from this instance of a defined and accepted body of work.
Alongside this usage was the promulgation of `canons' (`rules')
for the government of the Catholic Church.  The techspeak usages
("according to religious law") derive from this use of the Latin
`canon'.

Hackers invest this term with a playfulness that makes an ironic
contrast with its historical meaning.  A true story: One Bob
Sjoberg, new at the MIT AI Lab, expressed some annoyance at the
incessant use of jargon.  Over his loud objections, GLS and RMS
made a point of using as much of it as possible in his presence,
and eventually it began to sink in.  Finally, in one conversation,
he used the word `canonical' in jargon-like fashion without
thinking.  Steele: "Aha!  We've finally got you talking jargon
too!"  Stallman: "What did he say?"  Steele: "Bob just used
`canonical' in the canonical way."

Of course, canonicality depends on context, but it is implicitly
defined as the way *hackers* normally expect things to be.
Thus, a hacker may claim with a straight face that `according to
religious law' is *not* the canonical meaning of `canonical'.

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