# Types of Argument Indicators: Premise Indicators

30.01.2018

Episode #4 of the course Logic basics: Understanding arguments by Gary Curtis

In yesterday’s lesson, you learned about conclusion indicators. Today, we’ll talk about the other type of argument indicator: premise indicators.

Just as a conclusion indicator indicates a conclusion, a premise indicator indicates that a statement is a premise. Here are the most common premise indicators in English:

Warning: This list of indicators is not complete. An exhaustive list of English indicators doesn’t exist because one can always put together new phrases that serve the purpose.

Example (which you’ve seen before):

• “Since … all bodies, whether upon earth or in the heavens, are heavy … we must certainly allow that gravity is found in all bodies universally.” (Source: Preface to the second edition of Newton’s Principia)

“Since” is the only argument indicator word in this sentence, and it indicates that the statement immediately following is a premise: “All bodies, whether upon earth or in the heavens, are heavy.” The conclusion is not marked by any indicators, but it is the remainder of the sentence: We must certainly allow that gravity is found in all bodies universally.

Identifying Premise Indicators

All one-word premise indicators are ambiguous and serve other purposes than indicating premises. For this reason, identifying premises cannot be done in a mechanical way; you must attend to the meaning of the passage in which the indicator word or phrase occurs. One way to test whether such a phrase is functioning as a premise indicator is to substitute another premise indicator for it, and if the resulting sentence makes sense, the phrase probably indicates a premise.

Example: “[A Brief History of Time] was a remarkable success for a book that addressed some of the most difficult issues in modern physics. Yet those difficult issues are also the most exciting, for they address big, basic questions.” (Source: A Briefer History of Time, p.1)

The second occurrence of “for” in this passage is a premise indicator, and the premise is, “[those difficult issues] address big, basic questions.” The sentence still makes sense when “for the reason that” is substituted for the second “for”:

“[A Brief History of Time] was a remarkable success for a book that addressed some of the most difficult issues in modern physics. Yet those difficult issues are also the most exciting,” for the reason that “they address big, basic questions.” In this passage, the authors are trying to convince the reader that the difficult issues discussed in the book are exciting because they are “big” and “basic.”

However, the first occurrence of “for” in this passage is not a premise indicator. Substituting any of the indicator phrases for it produces ungrammatical gibberish; for instance:

“[A Brief History of Time] was a remarkable success” because “a book that addressed some of the most difficult issues in modern physics. Yet those difficult issues are also the most exciting, for they address big, basic questions.”

So, use premise indicators carefully, attending to the context in which they occur and using your understanding of its meaning. When in doubt, try the substitution test to see whether a word or phrase is a premise indicator.

In tomorrow’s lesson, you’ll learn how to tell the difference between an argument and an explanation.

Recommended book

An Illustrated Book of Bad Arguments by Ali Almossawi, Alejandro Giraldo

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