The arguer employs a three-part syllogism, but the logical connection between the premises and the conclusion is not established. Consequently, even if the premises are true, the conclusion will not necessarily follow.
Definition:
The Invalid Syllogism Fallacy is a formal error in logic in which the conclusion of an argument does not validly follow from its premises. A syllogism comprises two premises and a conclusion. This fallacy occurs when the rigorous rules of inference are violated, and the argument, despite having true premises, leads to a false conclusion. For example:
“All university professors have higher education. Daniel also has higher education. Therefore, Daniel is a university professor.”
Here, it should be noted that having higher education is a necessary condition for being a university professor, but it is not sufficient; many individuals have higher education without being university professors.
Typical structure of this fallacy:
- All A are B.
- C is a B.
- Therefore, C is an A.
This reasoning is invalid, because merely possessing the attribute B does not imply belonging to group A.
Examples from real life:
1. In science:
“All fish live in water. The dolphin lives in water. Therefore, the dolphin is a fish.”
Here, it should be noted that although both premises are true, the conclusion is false, since dolphins are mammals.
2. In politics:
“All democracies value social freedoms. We enjoy social freedoms in our country. Therefore, our country is a democracy.”
Here, it should be noted that certain social freedoms may exist to a limited extent under a non-democratic regime without the political system being democratic.
3. In economics:
“All successful economies have a free market. Country X has a free market. Therefore, Country X is successful.”
Here, it should be noted that a free market alone is not sufficient, and other factors such as transparency and judicial fairness are also necessary for a country’s success.
4. In everyday life:
“All those who have become wealthy have been hard-working. I am also hard-working. Therefore, I will become wealthy.”
Here, it should be noted that hard work is a necessary condition for becoming wealthy, but it is not a sufficient one.
5. In advertising:
“All quality products have elegant packaging. This product has elegant packaging. Therefore, this product is of high quality.”
Here, it should be noted that stylish packaging is not an independent criterion of quality.
Why is this fallacy dangerous?
● It leads to false conclusions: a person accepts an incorrect outcome because the premises appear to be true.
● It undermines the foundation of reasoning: it shows that a syllogistic appearance can be weak and deceptive.
● It oversimplifies complex relations: it reduces causal and logical issues to shallow and erroneous forms.
How can we recognise and respond to it?
If you see that the conclusion goes beyond the premises or does not necessarily follow from them, ask:
– “Is this conclusion the only logical outcome of these premises?”
– “Is it possible for the premises to be true but the conclusion false?”
– “Is there a logical gap between the premises and the conclusion?”
A suitable response might be: ‘Your premises may be true, but the conclusion drawn does not logically follow from them. Your argument involves an invalid syllogism and requires independent support.’
Conclusion:
The Invalid Syllogism Fallacy demonstrates that logic is not merely about the truth of the premises, but also about the way they are connected and inferred. Recognising this fallacy helps us distinguish between a valid argument and one that only appears logical but is in fact unsound.