Critical Thinking · Lesson 2 of 4

Assumptions, arguments and counterarguments

The assumptions nobody stated are where arguments usually fail, and they are findable in about two minutes.

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An argument is a set of reasons offered in support of a conclusion. Most arguments carry hidden assumptions — things that must be true for the reasons to connect to the conclusion, but which nobody stated because they seemed too obvious to say.

Finding those is the highest-yield critical move available to you. "We should raise prices because our costs went up" assumes customers will stay, that price is what is holding them, and that costs are the binding constraint. Each of those can be checked separately.

A counterargument is not an insult. The strongest version of the opposing case — stated so well that someone who holds it would say yes, that is what I mean — is the only real test an argument gets. If you cannot build it, you do not yet understand your own position well enough to trust it.

See it happen

"We should move the newsletter to Thursdays — open rates are higher on Thursdays."

The read that arrives on its own

Reasonable — the numbers say Thursday. You move the send day for next week.

The same situation, with this idea

Stated: Thursday opens are higher. Unstated: that the pattern comes from the day rather than from what we happen to send on Thursdays, that our readers behave like the benchmark, and that opens are what we are trying to move at all.

What changed

Nothing in the argument was false. Three assumptions were holding it up, and none of them had been said out loud — which is where arguments usually fail.

The takeaway

The assumptions nobody stated are where arguments usually fail, and they are findable in about two minutes.

Easy to take the wrong way

Hunting for assumptions only in arguments you dislike. The ones under a conclusion you already hold are the ones nobody ever goes looking for.

Try this

Write an argument you believe in one sentence. Then list three things that must be true for it to hold.