Some arguments are fallacious due to imprecise use of language. When a word, phrase, or sentence is used in different senses in course of an argument this type of fallacy is committed.
Fallacy of Equivocation:
This fallacy is committed when a key word or phrase is used with two or more different meanings in the same argument. The following arguments are guilty of committing this fallacy:
(I) “Since a criminal is a law breaker, a criminal lawyer too is a law breaker.” It can be noticed that the term ‘criminal’ has been used in two different senses in the argument. A criminal lawyer is not a criminal.
(ii) The signboard says “fine for parking here”. A driver notices the signboard and reasons as follows: “Since it is fine. I will park my vehicle here.” This surely is a misinterpretation. The word ‘fine’ has been used in two different senses here. In the signboard ‘fine’ means penalty. But the driver thinks that it means ‘all right’.
(iii) “Nature is governed by laws. Laws are the work of law makers. So, laws of nature are the work of some law maker.” In this argument the term ‘law’ has been used ambiguously. It means descriptive law in the first premise but used in the sense of prescriptive law in the second. Only prescriptive laws are the work of law makers. Laws of nature are descriptive laws and not prescriptive.
(iv) Really exciting novels are rare. But rare books are expensive. So, really exciting novels are expensive. Here the word ‘rare’ is used in different ways in the two premises of the argument. In the first premise ‘rare’ means extraordinary, whereas in the second it means novels that are scarce.
The construction of a sentence sometimes allows it to have two different meanings or interpretations. Amphiboly occurs when an arguer misinterprets a sentence that is syntactically or grammatically ambiguous and goes on to draw a conclusion on this faulty interpretation. This fallacy can also occur when someone is quoted out of context. The announcement that there will be a lecture on heart attack in the auditorium may be misinterpreted to mean that the lecture will be on heart attacks which have occurred in the auditorium. The ambiguity, however, can be clearly avoided if the phrase “in the auditorium” is placed immediately after “lecture” instead of “heart attack.”
The fallacy of accent occurs when emphasis is used to suggest a meaning different from the actual content of the proposition. For examples, if a teacher remarks, “Ravi has done the homework today” with undue emphasis on ‘today’, that might suggest that Ravi normally comes to school without doing homework.
Fallacy of Composition:
This fallacy occurs when an attribute true of the parts of something is erroneously transferred to the whole. Consider the following argument:
Each player in the team plays well.
Therefore, the whole team plays well.
This argument commits the fallacy of composition. From the fact that each individual player is a good player it doesn’t follow that the whole team plays well.
Fallacy of Division:
This fallacy occurs in an argument when an attribute true of a whole (or a class) is erroneously transferred to its parts (or members). Consider the following argument:
Men are numerous.
Aristotle is a man.
Therefore, Aristotle is numerous.
The argument is fallacious. It is true that “man” as a class has many members. So the class “man” as a whole is numerous. But we cannot draw the conclusion that each individual human being is numerous.