Identify the formal fallacy committed in the argument:

All criminals are human beings.

All saints are human beings

Therefore all saints are criminals.

Question

Question

This question was previously asked in

UGC NET Paper 1: Held on 12 Oct 2022 Shift 2

Answer 1

The correct answer is the Fallacy of undistributed Middle Term.

Important Points

In philosophy, a formal fallacy, deductive fallacy, logical fallacy, or non sequitur is a pattern of reasoning rendered invalid by a flaw in its logical structure that can neatly be expressed in a standard logic system, for example, propositional logic. It is defined as a deductive argument that is invalid.

Key Points

The fallacy of the undistributed middle (Latin: non-distributio medii) is a formal fallacy that is committed when the middle term in a categorical syllogism is not distributed in either the minor premise or the major premise. It is thus a syllogistic fallacy.
In classical syllogisms, all statements consist of two terms and are in the form of "A" (all), "E" (none), "I" (some), or "O" (some not).
The first term is distributed in A statements; the second is distributed in O statements; both are distributed in "E" statements, and none are distributed in I statements.
The fallacy of the undistributed middle occurs when the term that links the two premises is never distributed.
In this example, distribution is marked in boldface:
All criminals are human beings.
All saints are human beings.
Therefore, all saints are criminals.
Human being is the common term between the two premises (the middle term) but is never distributed, so this syllogism is invalid. Human beings would be distributed by introducing a premise that states either All human beings) are criminals or Some human beings are criminals.
Also, a related rule of logic is that anything distributed in the conclusion must be distributed in at least one premise.
All criminals are human beings.
Some Saint is criminal.
Therefore, all saints are human beings.
The middle term criminals is distributed, but saints are distributed in the conclusion and not in any premise, so this syllogism is invalid.