COMM 1117 Lecture 7: COMM 1117- Syllogism
2 May 2018
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Syllogism [RSP 57]
1. a specific way of arranging terms and statements
2. The statements that provide relevant information that are called the premises.
3. The statements that "follow" from the premises are called the conclusion.
• Figure out what follows from the premises that warrants the conclusion
EX) Premise: All people want to be treated equally by the justice system and police
o Premise: To be treated equally by the justice system and police is to be free from
racial profiling
o Conclusion: All people want to be free from racial profiling
• Distributed middle term drops out in the conclusion – same middle (but in
different sentence positions) term will be taken out of the first two premises and
then a conclusion is made
How is syllogism “valid”?
1. In a valid syllogism, the conclusion contains all of the information, and no more than that
information, contained in the premises.
• EX) If the conclusion sets forth more info than the premises set forth, the
conclusion does not “follow” the premises and is invalid
• EX) premise: all people want to be treated equally by the justice system and
police
• Premise: to be treated equally by the justice system and police is to be free from
racial profiling
• Conclusion: all people want to be free from racial profiling and any stop and frisk
searches
First test of validity
If the conclusion sets forth more information than the premises set forth, the conclusion does
not "follow" from the premises. The syllogism is invalid.
Second test of validity
If the conclusion sets forth information that conflicts with the information set forth in the
premises, the conclusion does not "follow" from the premises. The syllogism is invalid.
• EX)
o Premise: All people want to be treated equally by the justice system and police
o Premise: to be treated equally by the justice system and police is to be free from racial profiling
o Conclusion: only some people want to be free from racial profiling
o This syllogism is invalid because it contains info in the conclusion that conflicts with the info in the
premises.
