We explain what the analogy is, its use in argumentation, classification and examples. In addition, analogy in law and biology.
What is an analogy?
The analogy is a type of reasoning or expressive mechanism of language . It consists of comparing or relating various references : objects, reasons or ideas, to indicate general and particular characteristics in common, in order to justify the existence of a property in one of them.
This is, more easily said, that an analogy is a way of comparing a reference with another or others that are similar, but not identical, in order to attribute some characteristics determined by the set. The term comes from the ancient Greek ana- , “reiteration” and logos , “word” or “thought.”
The reasoning of the analogy can be represented by a general formula that would be “A is a B as C is a D”. The metaphor , simile, and homology comparison are tropes that can be considered analogies.
The analogy as a procedure is usually used in different areas of thought , from language and formal logic , to law , philosophy and even more specific areas, such as biology , where specific events with the same term are designated.
Types of analogy
Analogies can be classified according to their internal logical functioning, as follows:
- Symmetric analogy . Those in which the benchmarks compared can be exchanged without altering the relationships between them. That is, in which A, B, C and D are interchangeable because the relationship remains identical.
- Analogy asymmetric . Those in which the benchmarks compared cannot be exchanged, since their order of appearance designates a specific relationship. That is, that A is a B, like C to D, and not B is A, like C to D.
- Cause and effect analogy . Also known as association analogies, they suppose a specific link, of causality, between the referents. That is, A causes B, as C causes D.
- Analogy by reciprocity . It implies, in the relationship between the referents, a strict and reciprocal need between them, that is, for one to exist, the other must exist, reciprocally. That is, A requires absolutely B, as D absolutely requires C.
- Classification analogy . Those that work based on bringing together, in the same set of things, the related referents. That is, A and B are in the same set, just as B and C are in a similar set.
- Comparative analogy . Those that when checking references, seek to highlight a perceivable property. They usually use links and similes (“as”, “as”, “in the same way as”, etc.). That is, A is in such a way, as it is B.
- Analogy mathematics . Those that exist only between figures, numerical elements and mathematical proportions, given which the referents may have unequal values.
Examples of analogies
Here are some examples of analogies in the language:
- The wings are to the legs what the birds are to the people.
- Driver is a car as an airplane pilot and locomotive engineer.
- A painter paints a picture as a poet composes a poem.
- The sun is the food of plants.
- The stone is heavy as a guilty conscience.
- The night was dark as was the death.
- We are the Spartan warriors of this reading club.
- Maria is the Márgaret Thatcher of love.
Argument by analogy
While here we have seen the analogy as a rhetorical figure, that is, a particular use of language to reach higher expressive levels, it is also true that there is a kind of analogical reasoning, which consists in moving from the known to the unknown through of a comparison between referents.
This gives rise to four (main) argumentative forms based on the principle of analogy:
- Interpolation . It is based on the evaluation of all possible situations of an assumed or imaginary scenario and the repercussions of each one, and then moves to the analyzed situation. For example, suppose a man has two possible lovers, and refuses to decide for one. Then a friend advises him and tells him “who roasts two rabbits, one is burned”. The imaginary situation then serves to think the real one.
- Extrapolation . This procedure is widely used in problem solving and teaching, since it is part of the Scientific Method . It consists in assuming that the elements of a scenario will continue happening towards the future, thus allowing us to assume a new set of rules that would allow us, if true, to reach a new conclusion. For example, suppose a person is undecided as to who to vote between two candidates. A friend advises her and asks her to imagine what would happen if candidate A won, and then what would happen if candidate B won. From both scenarios they draw together new conclusions that serve to determine the vote.
- Reduction to the absurd . Its name comes from the Latin Reductio ad absurdum and serves to demonstrate the validity of categorical propositions. It consists in assuming the hypothetical denial of the validity of the premise, and then obtaining an illogical or fallacious conclusion through logical inferences. For example, suppose a child thinks the Earth is flat, and his teacher helps him prove that it is not. To do this, he asks him to assume that the Earth is not round, and how therefore it would be possible to reach the edge, or it would be possible to observe the Sun from any point on the planet. When verifying the absurdity of these logical consequences, the child must accept that the Earth is more likely to be round.
- Modeling . Especially important for the Scientific Method, modeling consists, as its name suggests, in the elaboration of a hypothetical model of reality , whose results may be analogous to those of reality, that is, they can be thought in analogical terms to the real . This, for example, occurs with mathematical models of economic behavior, which attempt to predict fluctuations in the world market or in certain currencies.
Analogy in law
In various branches of Law, analogy plays an important role in arguing about the resolution of a dilemma. In others, on the other hand, such as criminal law , the analogies are proscribed by the Principle of legality, which dictates that “there is no crime or penalty without prior law .”
In any case, the analogy in the law assumes that there must be a similarity between the planned and the unforeseen case , to avoid a radical difference between the two, since the law must be applied without legal loopholes.
This means that, given a past case that was resolved in some way, the same verdict could be applied to a different new case, as long as they have sufficient similarities.
In the field of biology and in particular evolution , it is known as an analogy to the superficial similarity between two or more organic structures that nevertheless have different origins . That is, they share essential features but do not come from an immediate common origin.
An example is the wings of a butterfly, a bat and a bird, since in all three cases they serve to fly, but they emerged at radically different evolutionary moments. Thus, these organisms have all wings, but they are not evolutionarily related, nor can they be grouped in that way.