Three ways to distinguish fact premises from claim premises:
(1) Claims sometimes predict the future, so you might see a future tense verb in them.
Example:
(Claim premise) If the farmers don't take action, the frost
will damage the orange crops. (Final conclusion) As a result, the cost of orange juice
will certainly increase.
Be careful, though, because sometimes you will see a future tense verb in a strictly fact premise.
Example:
The librarian has proposed an increase in the overdue book fee. She argues that since the fee
will be $7 a week (Fact premise), which exceeds the cost to purchase a paperback book, more people
will return library books on time (Final conclusion).
Here, the future tense is used because the fee is not assessed yet. But the librarian is taking the fee as fact when making her prediction about library patron behavior.
(2) There is wiggle room in modifiers, which can indicate claim premises. This is the issue in the example you cite.
hmgmat Wrote:However, I have a hard time to figure out whether a premise is a fact or a claim. For instance, OG11(yellow)#113 explanation refutes a premise -- aircraft are free-wheel systems. By reading the passage, such premise sounds like a fact to me.
Aircraft = Free-wheel system. True, and that means airplanes can fly anywhere. But it doesn't mean they can land anywhere. The correct answer to that question isn't so much
refuting the premise as it is
further clarifying the modifier "free-wheel system."
Other examples:
The
difficulty with the plan is... (it's someone's opinion that there is a "difficulty")
Troubling developments at the school district... (what exactly makes them "troubling"?)
(3) Ask yourself whether the speaker/author is taking the premise as fact, or whether the author is aware that he/she is making a prediction or stating an opinion.
Finally, remember that the main reason to distinguish fact premises and claim premises is to avoid confusing claim premises with the final conclusion.