Since any existing thing, whether natural or invented, must apparently obey the
fundamental laws of physics, the difference between the two must be determined
not through actual function, but through some other measure, such as whether the
item in question came to exist through accident
or intent.
For the
purposes of the Language of Metaphors, these are considered mere matters of
perspective, thus are afforded the value of "equal". No doubt it was
the nature of a leech to suck nutritious blood, for example, before it became an invention
for the removal of bad blood by ancient doctors.
A true antithesis, it
could be said, is an equal, opposed along the measure in question. Without a
direct historical record, judging whether a given event was accidental or
intentional is arguably impossible; this is as true with natural and invented
objects.
Metaphors can apply a valuation based on the accepted contemporary public (or
target demographic) sentiments. Today we value "natural" and
"biodegradable" - thus sales of green packaging ink have surely risen
in concert. Fifty years ago, however, the sharp angles, perfect painted finishes
and frequent use of the theme "modern" denoted a sense of
"invented = hip".
One is free to set the tone of ones metaphors to suit their needs,
providing, for example, a sense that a "higher power created us", or a
contrasting sense of fallibility with "human nature". When
perspective is built into a metaphor, it can shape both the body of the
message, and the values attached to it. An entertaining test of this is to
look at the names of cars and motorcycles invented in each decade and
compare them with the culture surrounding them: animals may have made good
metaphors during one era, where weapons or adventurism may appeal at other
times.
An intention is a planned accident: "If all
goes according to plan."
An accident is an unplanned plan: "The best-laid
schemes o'
mice an
'men Gang aft
agley...!"