[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 Cal
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'.
