| An analogy is a comparison between two different things, in order to
highlight some form of similarity.
Analogies are often used to explain new or complex concepts by showing the
similarity between something familiar and something else.
Analogy types
Linguistics
- In linguistics, an analogy can be a spoken or textual comparison between two words (or sets of words) to highlight
some form of semantical similarity between them. Linguistical analogies can be
used to strengthen political and philosophical arguments, even when the semantical similarity is
weak or non-existent (if crafted carefully for the audience).
- An analogy can also be the linguistical process that reduces word forms perceived as irregular by remaking them in the shape of more common
forms that are governed by rules. For example, the English verb help once had the preterite holp and the past
participle holpen. These obsolete forms have been discarded and replaced by
helped by the power of analogy. However, irregular forms can sometimes be created by analogy; one example is the American English past tense form of "dive": "dove", formed on analogy with
words such as drive-drove.
- Neologisms can be formed by analogy with existing words. A common example
is software, formed by analogy with hardware. Another example is the humorous term underwhelm, formed by analogy with
overwhelm.
Mathematics
Some types of analogies can have a precise mathematical formulation
through the concept of isomorphism.
Anatomy
- See also: Analogy (biology)
In anatomy, two anatomical structures are considered to be analogous when
they serve similar functions but are not evolutionarily related, such as the legs of vertebrates and the legs of insects. Analogous structures are the
result of convergent evolution and should be contrasted
with homologous structures.
Law
In law, analogy is used to resolve issues on which there is no previous authority. A
distinction has to be made between analogous reasoning from written law and analogy to precedent case law.
Analogies from codes and statutes
In civil law systems, where the preeminent
source of law are legal codes and statutes, a lacuna arises when a specific issue is not explicitly dealt
with in written law. Judges will try to identify a provision whose purpose applies to the case at hand. That process can reach a
high degree of sophistication, as judges sometimes not only look at specific provision to fill lacunae (gaps), but at at several
provisions (from which an underlying purpose can be inferred) or at general principles of the law to identify the legislator's
value judgement from which the analogy is drawn.
Analogies from precedent case law
By contrast, in common law systems, where precedent cases are the primary
source of law, analogies to codes and statutes are rare (since those are not seen as a coherent system, but as incursions into
the common law). Analogies are thus usually drawn from precedent cases: The judge finds that the facts of another case are
similar to the one at hand to an extent that the analogous application of the rule established in the previous case is
justified.
Linguistic example
The United States-based SAT college entrance
test includes "analogy" questions that ask for comparisons between analogies: A is to B as C is to what? For
example:
- Hand is to palm as foot is to ____?
These questions are usually given in the format:
- HAND : PALM : : FOOT : ____
External links
References
Holyoak, K.J. et. al. (1996). Mental Leaps: Analogy in Creative Thought. Cambridge, Massachusetts, The MIT Press.
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