Logical fallacy problems: straw men, false choices and weak causation

What to take away

Fallacy names are useful only when they help repair reasoning. Calling a paragraph "a straw man" without identifying the distortion leaves the writer little to revise. This guide pairs each common problem with a test and a concrete fix.

Problem 1: The straw man

A straw man misstates an opposing position so it becomes easier to reject.

Draft: "Supporters of slower downtown traffic want to ban cars."

Suppose the documented proposal calls for a 20 mph limit on three streets. The draft has changed a speed rule into a vehicle ban.

Diagnostic questions:

Repair: quote or paraphrase the proposal at its strongest supported scope, explain why a reasonable person could accept it, and answer that version.

Purdue OWL's guide to common logical fallacies defines the straw man as an oversimplified opposing view and the either-or fallacy as reducing a complex issue to two choices. Its practical warning is that a distorted opponent does not establish the writer's own conclusion.

Problem 2: The false choice

A false choice presents two options as exhaustive when other positions, hybrids, degrees, or sequences remain possible.

Draft: "Either the museum digitizes its entire archive now or it does not care about access."

Repair with an option matrix:

Then defend a choice against the real alternatives.

Problem 3: Weak causation

Draft: "Complaints fell after the new form launched, so the form solved the problem."

The timing is compatible with that explanation, but it does not isolate it. Reporting behavior, staffing, seasonality, eligibility, and counting rules may have changed.

Use a causal repair sequence:

Safer revision: "Recorded complaints declined after the form launched, but the available records do not separate the form's effect from staffing and reporting changes."

Problem 4: Moving the goalposts

This problem occurs when the required proof changes after the other side meets the stated standard.

Standards can be revised for good reasons, such as discovering that the first measure was inadequate. The error lies in changing them opportunistically while pretending the original standard was never met.

Repair: define the burden before evaluating evidence. If it changes, state why, apply the new rule consistently, and acknowledge what the earlier evidence established.

Problem 5: Slippery chains without support

A policy may have downstream effects, but a chain needs support at each step.

Draft: "Allowing one late assignment will erase all deadlines, collapse course standards, and make grades meaningless."

The MIT OpenCourseWare handout on logical fallacies describes a slippery-slope argument as claiming that one action must lead to a sequence of consequences without sufficient justification. To repair the passage, support the probability and mechanism of each transition or stop where the evidence stops.

Problem 6: Conclusion drift

An essay may begin with one claim and end with a larger one.

Draw a boundary around population, measure, setting, and time. Copy those boundaries into the conclusion. A preference is not necessarily a learning outcome, and two classes are not all universities.

A repair table

Common questions

Does using a fallacy label prove an argument is wrong?

No. Show the specific premise, inference, or representation that fails.

Can a two-option choice ever be fair?

Yes. Demonstrate that the options are exhaustive under the stated conditions.

Is correlation useless?

No. It can describe a relationship and motivate further inquiry. It simply does not establish cause by itself.

Is changing an evidence standard always unfair?

No. New information can expose a bad standard. Explain the revision and apply it consistently.