Enthymeme

Breaking Down Enthymematic Reasonings

Enthymeme (derives from Greek ‘enthumēma’ literally means “a thought” or “a consideration” ), is a figure of reasoning whereby either the major or minor premise in which the argument is based is deliberately omitted and left to be understood.

The enthymeme is a kind of syllogismOpens in new window, and deduced from few premises, often from fewer than the regular syllogism; for if any one of these is well known, there is no need to mention it, for the audience will instinctively add it. However, assuming the omitted premise or conclusion is explicitly supplied, the argument would be rendered invalid. This is by some scholars considered an informal means of expressing syllogismOpens in new window.

In a typical enthymematic argument, the conclusion is stated in the first claim, and a minor premise is stated as the reason given for that claim, often expressed in a “because clause”. For sake of clarity, we analyse the proposition below:

All good nations are great nations. Major Premise
America is a good nation. Minor Premise
America is a great nation. Conclusion

The above propositions are syllogistic argument and can be rendered in form of enthymematic statement by asserting that:

  • “America is a great nation, because she is a good nation (leaving out the major premise).
Or alternatively,
  • “Since all good nations are great nations, America is therefore a great nation (leaving out the minor premise).

In some cases, propositions may be stated implicitly in an enthymeme because either they are quite obvious or explicitly stating them could thaw the flow of the argument—thereby rendering it formally invalid.

Another important reason some orators would rather imply a conclusion or premise would be to give the audience room to infer it; the initiative being that audience are more persuaded by the context of the argument if they have to draw out the premise or conclusion by their own will.

Examples of Enthymeme

The following are examples of enthymeme derives from syllogism through truncation (shortening) of the syllogism:

1.  
  • “We cannot trust this man, for he has perjured himself in the past.”

In this enthymeme, the major premise of the complete syllogism is missing. The complete formal syllogism would be the classic:

Major premise (omitted)
  • Those who perjure themselves cannot be trusted.
Minor premise (stated)
  • This man has perjured himself in the past.
Conclusion (stated)
  • This man is not to be trusted.
2.  
  • “Socrates is mortal because he's human.”

The complete formal syllogism would be the classic:

Major premise (omitted)
  • All humans are mortal.
Minor premise (omitted)
  • Socrates is human.
Conclusion (stated)
  • Therefore, Socrates is mortal.
3.  
  • “It is quite recent history, Lord Randolph was Chancellor of the Exchequer, Lord Salisbury was Prime Minister, as he is now. And on this same issue of economy Lord Randolph Churchill went down forever. But wise words, Sir, stand the test of time. And his words were wise.” (excerpt from the "Young Winston"

The complete enthymematic statement would be thus:

Major premise (omitted)
  • Wise words stand the test of time.
Minor premise (omitted)
  • [Lord Churchill's] words were wise
Conclusion (stated)
  • [Lord Churchill's] words will stand the test of time.
4.  
  • “You'll do fine, just follow your heart.”

The omitted premise necessary for validity in the argument would be “All persons who follow their heart are persons who do fine.”

Major premise (omitted)
  • All persons who follow their heart are persons who do fine.
Minor premise (omitted)
  • You are a person who follows your heart.
Conclusion (stated)
  • You are a person who does fine.

In other cases, if the missing proposition were present explicitly, the argument might lose rhetorical force.

    For example:
  • “Gretchen does well because she pays attention.”

Here, the implied premise necessary for validity would be “All people paying attention are people who do well.” (Note that it seems reasonable that some persons who pay attention might not do well.) And so, the argument when stated explicitly becomes:

Major premise (omitted)
  • All persons paying attention are people who do well.
Minor premise (omitted)
  • You are a person who pays attention.
Conclusion (stated)
  • Gretchen is a person who does well

Occasionally, a proposition is suppressed in an effort to conceal the unsoundness or the invalidity of the argument,

    For Example:
  • No cars with internal combustion engines are energy efficient, so no American-made cars are energy efficient.

The omitted premise necessary for validity here is the false premise, "All American-made cars are cars with internal combustion engines." The reconstructed argument, then looks like this:

Major premise (omitted)
  • No cars with internal combustion engines are energy efficient.
Minor premise (omitted)
  • All American-made cars are cars with internal combustion engines.
Conclusion (stated)
  • No American-made cars are cars with internal combustion engines.

In this case, yet again, the argument is valid, but unsound.

Further Readings:
Silva Rhetoricae, Figures | enthymemeOpens in new window
www.csuchico.edu/phil/sdobra_mat/enthymemes | syllogism and enthymemeOpens in new window
Analysing Enthymatic Arguments | enthymatic argumentOpens in new window
American Rhetoric | enthymemeOpens in new window