What does syllogism mean?
A syllogism is a form of logical reasoning that typically consists of two premises and a conclusion. The first premise establishes a general relationship, the second applies that relationship to a particular case, and the conclusion states what follows. Classical examples often take the form “All A are B; all C are A; therefore, all C are B.” The word is especially common in philosophy, logic, rhetoric, and academic criticism, where it can describe either a valid deduction or an argument presented as one. In everyday language, “syllogism” may also refer more loosely to a chain of reasoning, often with the suggestion that the chain is incomplete or misleading. Understanding the term helps distinguish sound deductive reasoning from arguments that reach a conclusion without genuinely establishing it.
nounA logical argument consisting of two premises and a conclusion, where the conclusion is inferred from the premises. In its strictest sense, a syllogism is a valid deductive argument with exactly three terms.
- A deductive argument in which a conclusion follows from two stated premises.
- Broadly, any formal reasoning structured as a chain of related propositions.
"The argument that all poets are dreamers, that this writer is a poet, and therefore that this writer is a dreamer is a syllogism."
"The teacher asked the class to identify the flaw in the syllogism."
"His argument rested on a familiar syllogism about wealth, education, and social advantage."
The regular plural is syllogisms, used when referring to multiple logical arguments or examples of syllogistic reasoning.
"The chapter compares several famous syllogisms and evaluates whether each is formally valid."
A syllogism is logic compressed into three parts: two premises and the conclusion they support.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does syllogism come from?
The word comes from Latin syllogismus, itself borrowed from Greek syllogismos, “a putting together, calculation, or logical argument.” Greek syllogizein meant “to put together” and was built from syn-, “together,” and logos, “word, reason, or account.” The same Greek root underlies words such as logic and syllogize, while syllogistic and syllogistically are later English derivatives.
Related word forms
How syllogism is actually used
In academic and formal contexts, it usually refers specifically to a traditional deductive argument with two premises and a conclusion. In general discussion, it may be used more broadly for a carefully structured logical argument, sometimes even with a dismissive implication when the reasoning is simplistic.
Easily confused with syllogism
A syllogism is a form of logical reasoning, whereas a syllogy is a collection of words, especially a mnemonic list used to aid pronunciation.