Definition of Syllogism

A syllogism is a form of logical reasoning that joins two or more premises to arrive at a conclusion. For example: “All birds lay eggs. A swan is a bird. Therefore, a swan lays eggs.” Syllogisms contain a major premise and a minor premise to create the conclusion, i.e., a more general statement and a more specific statement. In the example, 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. Syllogistic arguments are generally presented in this three-line format.

The word syllogism comes from the Greek word syllogismos, which means “a conclusion” or “inference.” The definition of syllogism is very similar to that of enthymeme. In an enthymeme, one of the premises—either major or minor—is implied and thus left out of the reasoning. Even the conclusion can be omitted in an enthymeme because it is obvious enough to the reader or listener.

Types of Syllogism

While the most basic type of syllogism takes the form of “All A are B. All C are A. Therefore all C are B,” there are, in fact, about two dozen types of syllogisms. Here are just a few different ways that statements can be combined to form conclusions:

  • No A are B. All C are A. Therefore, no C are B. Example: No dogs are cats. All beagles are dogs. Therefore, no beagles are cats.
  • All A are B. Some C are A. Therefore, some C are B. Example: All carnivores eat meat. Some mammals are carnivores. Therefore, some mammals eat meat.
  • Some A are B. All A are C. Therefore, some C are B. Some men eat meat. All men are humans. Therefore, some humans eat meat.

Syllogistic Fallacies

Syllogisms can seem so logically precise that they present airtight arguments. However, it is quite clear to see how there could be fallacy examples in syllogisms if one or more of the premises is incorrect, or a faulty conclusion is drawn when the premises are not absolute. Here are some examples of syllogism that have inherent flaws:

  • All men have brains. All humans have brains. Therefore, all humans are men.
  • Some horses are brown. Some shoes are brown. Therefore, some horses are shoes.
  • All carrots are orange. Some cats are orange. Therefore, some cats are carrots.

Note that in all of these examples, the premises are all true. It is also possible that the premises themselves are incorrect. For example: All humans are moral. I am a human. Therefore, I am moral. In this case, the conclusion is not borne out because it is false to state that all humans are inherently moral creatures. Though the speaker could be a moral human being, the syllogistic form cannot support this conclusion.

Common Examples of Syllogism

There are some examples of syllogism in popular culture, such as in advertising and television.


Dr. House: Words have set meanings for a reason. If you see an animal like Bill and you try to play fetch, Bill’s going to eat you, because Bill’s a bear.
Little Girl: Bill has fur, four legs, and a collar. He’s a dog.
Dr. House: You see, that’s what’s called a faulty syllogism; just because you call Bill a dog doesn’t mean that he is . . . a dog.

(“Merry Little Christmas” episode from House, M.D.)

Jaqen H’ghar: A man pays his debts. A man owes three.
Arya Stark: Three what?
Jaqen H’ghar: The Red God takes what is his, lovely girl. And only death may pay for life. You saved me and the two I was with. You stole three deaths from the Red God. We have to give them back. Speak three names, and a man will do the rest. Three lives I will give you. No more, no less. And we’re done.

(“The Ghost of Harrenhal” episode from Games of Thrones)
In this example, the character Jaqen H’ghar is presenting this syllogism: Only death can pay for life. You saved three lives. Therefore, I must kill three men.


  • “With a name like Smucker’s, it has to be good.” —Smucker’s jams
  • “These are the stakes–to make a world in which all God’s children can live or go into the dark. We must either love each other or we must die.” —Presidential Candidate Lyndon Johnson’s “Daisy commercial”
  • “Want him to be more of a man? Try being more of a woman!” —Coty perfume

Significance of Syllogism in Literature

Syllogism has been an important part of logic for thousands of years, especially popularized by Aristotle. One of his most famous syllogistic statements was the following: “All men are mortal. Socrates is a man. Therefore, Socrates is mortal.” Scholars during the Middle Ages also took up the analysis of syllogisms and eighteenth and nineteenth century scholars such as Immanuel Kant and George Boole also discussed the importance of syllogistic reasoning. Even René Descartes famous statement “Cogito ergo sum,” translated into English as “I think, therefore I am,” is an example of syllogism. While it is important in logic, it is more difficult to find syllogism examples in literature, as writers are usually not quite as explicit in their reasoning as syllogism tends to be. However, some authors have characters use syllogism to prove a point, while others use it subtly to describe a situation. Generally, when syllogistic reasoning is found in literature, it is not as explicit as the three-part structure we see in logic.

Examples of Syllogism in Literature

Example #1

All love is wonder; if we justly do
Account her wonderful, why not lovely too?

(“The Anagram” by John Donne)

This is an example of syllogism that presents the premises and conclusion in a relatively straightforward manner. As the poet John Donne writes about his love, he posits the following about his beloved: All love is wonderful. She is wonderful. Therefore, she is lovely. Of course, whether or not this is true about the woman, Donne employs a bit of false reasoning here. A correct syllogism would be: All love is wonderful. She is love. Therefore, she is wonderful.

Example #2

“Who chooseth me shall gain what many men desire.”
Why, that’s the lady. All the world desires her.

(The Merchant of Venice by William Shakespeare)

In William Shakespeare’s play The Merchant of Venice, several suitors come to woo Portia and are confronted with the riddle of the three chests—gold, silver, and lead. The man who correctly chooses the chest that contains Portia’s portrait can marry her. The Prince of Morocco reads the description of the golden chest, which is stated above, and makes the following syllogistic argument: All the world desires Portia. The golden chest contains what many men desire. Therefore, the golden chest contains Portia’s portrait. Unfortunately for him, he gets the riddle wrong.

Example #3

All animals are equal, but some animals are more equal than others.

(Animal Farm by George Orwell)

There are several misconstructions of logic and reasoning in George Orwell’s novel Animal Farm. The animals who take control of the farm from humans make some new rules and manifestos. At the beginning of the story, the pigs—who create these new rules—assert that all animals are equal. Later in the novel as some pigs become power hungry, the syllogism grows and changes, and becomes absurd. The above syllogism example implies: All animals are equal. Some animals are more equal than others. Therefore, pigs are more important than other animals. This is an example where the conclusion is left out.

Test Your Knowledge of Syllogism

1. Which of the following statements is the best syllogism definition?
A. A set of propositions that lead to a conclusion.
B. A series of premises in which false arguments are made.
C. A way to convince people of something that is not true.

Answer to Question #1 Show

2. Which of the following statements is an example of syllogistic fallacy?
A. No reptiles have fur. Some reptiles are lizards. Therefore, no lizards have fur.
B. Some mammals live in the water. All sharks live in the water. Therefore, some mammals are sharks.
C. No homework is fun. Some reading is homework. Therefore, some reading is not fun.

Answer to Question #2 Show

3. Consider the following quote from George Orwell’s novel Animal Farm:

Four legs good, two legs bad.

Which of the following syllogisms—faulty or not—does this mean to imply?
A. No animals have three legs. All animals have either four or two legs. Some animals are good, and others are bad.
B. Some animals have four legs and some animals have two legs; those that have four legs are good.
C. All animals walk on four legs and all humans walk on two legs; thus, all animals are good and all humans are bad.

Answer to Question #3 Show

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