Syllogism: Definition with Examples in English

Syllogism is a form of logical thinking that joins two or more structures to the conclusion. For example: “All birds lay eggs. A swan is a bird. Therefore, a swan lays eggs.”

Syllogisms contain a large base and a small basis for conclusion, that is, a general statement and a more detailed statement. In the example above, the major premise is that all birds lay eggs. The minor premise is that a swan is a bird. The conclusion links these two propositions to conclude that if a swan is a bird it must lay eggs. 

In other words, Syllogism is a form of diminishing thinking when you come to a certain conclusion by exploring other structures or two ideas.

Some syllogisms contain three components:

  • Major Premise
  • Minor Premise
  • Conclusion

For example, all roses are flowers (major premise). This is a rose (minor premise). Therefore, I am holding a flower (conclusion).

3 Types of Syllogism

There are three types of syllogism which we are going to explain in details with the help of examples:

  1. Categorical syllogisms follows “If A is part of C, then B is part of C” logic.
  2. Conditional syllogisms follow an “If A is true, then B is true” pattern of logic.
  3. Disjunctive syllogisms follow a “Either A or B is true, if it’s A, B is false” premise. They don’t state if a major or minor premise is correct. But it’s understood that one of them is correct.

Examples of Syllogisms

Let us work on some other interesting examples:

  1. He couldn’t have stolen the jewelry. I know him.
  2. Major Premise: He couldn’t have stolen the jewelry.
  3. Minor Premise: I know his character.
  • Her new purse can’t be ugly. It’s a Louis Vuitton.
  • Major Premise: Her new accessory can’t be ugly.
  • Minor Premise: It’s made by famous designer Louis Vuitton.

The above is enthymeme which is a type of syllogism. In the examples above, being familiar with someone or something implies an understanding of them.

  1. All crows are black. The bird in my cage is black. Therefore, this bird is a crow.
  2. Major Premise: All crows are black.
  3. Minor Premise: The bird in my cage is black.
  4. Conclusion: This bird is a crow.
  • The scenery in Ireland is beautiful. I’m in Ireland. Therefore, the scenery must be beautiful.
  • Major Premise: The scenery in Ireland is beautiful.
  • Minor Premise: I’m in Ireland.
  • Conclusion: The scenery is beautiful.

The above is an example of Syllogistic Fallacy. Of course, not all black birds are crows and not all of Ireland is beautiful. When preparing a talk or writing a paper, we should always be careful not to do anything that would cause others to think that way.

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Types of Logical FallaciesExamples of Analogy