The illicit minor fallacy occurs when, in the premise of an argument, reference is made only to part of a group, but in the conclusion, a claim is wrongly made about the entire group.
Definition:
This fallacy occurs when the minor term [1] in the minor premise is mentioned only in a partial sense (for example, with the phrase “some of…”), but in the conclusion, the same group is treated as universal. In such a case, the conclusion exceeds the scope of the premises and the syllogism becomes invalid, because a judgement about part of a group is unjustifiably extended to the whole group. This is what is called the illicit minor fallacy. For example:
“All body-building athletes are healthy. [Major premise]
Some students at this school are body-building athletes. [Minor premise]
Therefore, all students at this school are healthy. [Conclusion]”
Here, it should be noted that “the students at this school” is the minor term. In the minor premise, this group is mentioned only partially, meaning the statement refers to “some” students, not all. In the conclusion, however, the same group is treated as universal, and health is attributed to “all” students. This is the unwarranted leap from the particular to the general, which makes the reasoning invalid and is a clear example of the illicit minor fallacy.
Now that we have seen how this type of reasoning becomes invalid, and will encounter further examples below, it is helpful first to understand what a valid syllogism looks like—something the illicit minor fallacy fails to achieve.
In a valid syllogism, if the subject of the conclusion (the minor term) is used universally, it must also be stated universally in the minor premise. If the premise refers only to “some” members of a group, a universal conclusion about “all” cannot be drawn. For example:
“All member states of the United Nations are obliged to observe its Charter.
All European countries are member states of the United Nations.
Therefore, all European countries are obliged to observe the UN Charter.”
Here, it should be noted that “European countries” is the minor term, which is used universally both in the minor premise and in the conclusion. In the minor premise, it is stated that “all European countries are member states of the United Nations”, and in the conclusion, the judgement is likewise made universally about the same group. The major term, “being obliged to observe the UN Charter”, is also stated universally in the major premise. Thus, none of the terms extend beyond the premises, and the scope of the conclusion is exactly consistent with them. For this reason, this is a valid syllogism.
Typical structure of this fallacy:
- Major premise: All M are P.
- Minor premise: Some S are M.
- Conclusion: Therefore, all S are P.
Examples from real life:
1. In politics:
“All dictators are dangerous. [Major premise]
Some leaders of Region A are dictators. [Minor premise]
Therefore, all leaders of Region A are dangerous. [Conclusion]”
Here, it should be noted that “the leaders of Region A” is mentioned only partially in the minor premise, but in the conclusion it is unjustifiably applied to all leaders. Such reasoning can serve as a pretext for discrediting or sanctioning an entire country.
2. In media and advertising:
“Any news from an official source is reliable. [Major premise]
Some reports on this channel come from an official source. [Minor premise]
Therefore, all reports on this channel are reliable. [Conclusion]”
Here, it should be noted that the minor premise refers only to the official origin of some reports, but in the conclusion all reports on the channel are presented as reliable. This fallacy is a tool for winning public trust in a media outlet that may also publish false news.
3. In education:
“Every hard-working person is successful. [Major premise]
Some students at this school are hard-working. [Minor premise]
Therefore, all students at this school are successful. [Conclusion]”
Here, it should be noted that the minor premise refers only to the hard work of some students at the school, but in the conclusion all students are presented as successful.
This is the illicit extension of the minor term, which renders the argument invalid. Such a fallacy may be used in educational advertising or by school administrators to present an idealised and unrealistic picture of all students.
4. In consumer economics:
a) “All organic products are healthy and harmless. [Major premise]
Some products of this brand are organic. [Minor premise]
Therefore, all products of this brand are healthy and harmless. [Conclusion]”
Here, it should be noted that the minor premise refers only to the organic nature of some products of the brand, but in the conclusion all of its products are presented as healthy and harmless. This is the illicit extension of the minor term, which makes the argument invalid. Such a fallacy is often seen in food advertising and marketing, where companies highlight a limited positive feature (the fact that some products are organic) to create a positive image of the whole brand and persuade consumers to buy all their products.
b) “All medicines of this company are effective. [Major premise]
Some products of this company are medicines. [Minor premise]
Therefore, all products of this company are effective. [Conclusion]”
Here, it should be noted that “the products of this company” is the minor term. In the minor premise, reference is made only to part of these products, namely “some products of this company are medicines”. In the conclusion, however, the same group is treated universally and the quality of “being effective” is extended to all the company’s products. This is the illicit extension of the minor term, which makes the reasoning invalid. Such a fallacy can be used in pharmaceutical and commercial advertising, where a company relies on the effectiveness of a few medicines to create a general and positive image of all its products.
5. In everyday life:
a) “Every foreign sweet is delicious. [Major premise]
Some sweets in this confectionery are foreign. [Minor premise]
Therefore, all sweets in this confectionery are delicious. [Conclusion]”
Here, it should be noted that the minor premise refers only to the foreign origin of some sweets in the confectionery, but in the conclusion all of its sweets are presented as delicious. This is the illicit extension of the minor term, which makes the argument invalid. Such a fallacy can be seen in confectionery or grocery advertising, where a few tasty foreign products are highlighted to create the impression that all items sold there are delicious and of high quality.
b) “Every athlete is healthy. [Major premise]
Some of my neighbours are athletes. [Minor premise]
Therefore, all of my neighbours are healthy. [Conclusion]”
Here, it should be noted that the minor premise refers only to the athletic status of some neighbours, but in the conclusion all neighbours are presented as healthy. This is the illicit extension of the minor term, which makes the reasoning invalid. Such a fallacy in everyday life can lead to unrealistic assumptions or simplistic stereotypes, for example the mistaken belief that because a few neighbours are athletes, all neighbours must be healthy.
Why is this fallacy dangerous?
- Unjustified generalisation: A quality that belongs only to part of a group is extended to the whole group.
- A tool for political and advertising purposes: This fallacy can be used to discredit one group or to make another appear praiseworthy without reason.
- Hidden deception: Its seemingly logical form causes many people to accept the false conclusion without careful thought and fall into the trap of deception.
How can we recognise it and respond?
Look at the conclusion and ask:
– Has the minor term been stated universally in the minor premise, or only partially?
– Does the minor premise use words such as “some”, “a few”, or “several”, while the conclusion uses “all” or “every”?
A suitable response might be: “You have extended a feature that applies only to some people or items to all of them. This leap from the particular to the universal makes your reasoning invalid.”
Conclusion:
The illicit minor fallacy reminds us that no conclusion should go beyond the premises. For example, if a premise refers only to some members of a group, we cannot conclude that all of that group, or similar groups, share the same feature. Careful attention to the role of the minor term in a syllogism protects us from this logical error and its social and political consequences [2].
[1] The minor term in a syllogism is the subject of the conclusion. It is the same group or concept that appears in the minor premise and is repeated in the conclusion. For example, in the syllogism “All member states of the United Nations are obliged to observe its Charter / All European countries are member states of the United Nations / Therefore, all European countries are obliged to observe the UN Charter”, the phrase “European countries” is the minor term, which appears both in the minor premise and in the conclusion.
[2] Studying the illicit minor fallacy shows that many stereotypes and forms of discrimination have their roots in such unwarranted leaps. True philosophy, unlike academic philosophy, stresses that no partial feature should ever be generalised to an entire group. Precision in the meaning and scope of concepts can prevent political and promotional misuse and can contribute to the protection of human rights and the promotion of lasting peace.