canonical adj.
[very common; historically, `according to religious law'] 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 present loading
in computer-science culture largely through its prominence in
Alonzo Church's work in computation theory and mathematical logic
(see Knights
of the Lambda Calculus). Compare vanilla.
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' has an interesting history. It 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'.