Flaws

Misdirected Response

When the author or second speaker responds to an argument the other person never actually made.

The response aims for the wrong target.

LSAT Wording: “Is directed toward disproving a claim that was not made.”

False Dichotomy

When you think you are limited to two options, even though there might be other ones available.

LSAT Wording: “Assumes without warrant that a situation allows only two possibilities.”

Confusing a Mental State with Reality

When you mix up a fact about the world with someone’s belief or intention (what is happening in their mind); or the other way around.

LSAT Wording: “Assumes that because an action was followed by a change the action was undertaken for the purpose of bringing about that change.”

Confusing a Lack of Support with a False Conclusion

When you think knocking down someone’s argument proves that their conclusion is wrong.

This is a flaw because the conclusion can still stand, even if you take away it’s support.

LSAT Wording: “Rejects a position on the grounds that an inadequate argument has been made for it.”

Attacking the Source

When you attack the person/characteristic that holds a view rather than the view itself.

Whether someone is biased or hypocritical doesn’t affect whether their view is true.

LSAT Wording: “Attacks the proponent of a claim rather than the merits of the claim.”

Overlooking Factors

Happens when you base a judgement on only some of the factors that matter.

Weighing a cost or benefit but ignoring the other side, or fixating on one effect while ignoring the ones that push the other way.

LSAT Wording: “Fails to consider that the benefits to be gained might outweigh the costs.”

Part v. Whole

When you assume that something true about the individual components of a thing must also be true about the whole thing (or the other way around).

LSAT Wording: “Assumes that because something is true of each of the parts of a whole, it is true of the whole itself.”

Unrepresentative Sample

When you generalize about a group based on a slice of it that’s skewed in a relevant way.

LSAT Wording: “The argument draws a conclusion about a population from observations of a subgroup that is quite likely to be unrepresentative of that population in certain relevant respects.”

Assuming Cause from Correlation

Happens when you think that the fact two things tend to show up together proves that one thing must have caused the other.

There could be other explanations for why the two things show up together (ex. Third factor that causes both, or causal direction is reversed).

LSAT Wording: “Illicitly infers a cause from correlation.”

Confusing Sufficient and Necessary Conditions

Happens when you think something that guarantees another thing is absolutely required for that thing (or the other way around).

LSAT Wording: “Takes a sufficient condition as a necessary one.”

Percentage / Quantity Fallacy

Sometimes an argument uses a quantity when what is really needed to support an argument is a percentage.

Remember, RAW numbers without context cannot prove relative danger or frequency. Always compare rates, not quantifies, when making safety claims.

Relative / Absolute

A relative term is one that compares something to something else.

Saying, “Jerry runs faster than Larry,” is in relative terms. Jerry is “faster” in relative terms to Larry, but that doesn’t tell us whether Jerry is actually a fast runner in absolute terms.

Perhaps, Jerry and Larry are both very slow. So, it is important to take note of when things are presented in relative terms like “better than,” “faster than,” “taller than” vs. absolute terms like “good”, “fast,” or “tall.”

Absence of Evidence v. Evidence of Absence

Just because there is no evidence that something is true, does not mean that it is false.

Even a complete lack of evidence supporting a claim is not grounds to regard the conclusion as false.

Slippery Slope (Rare)

Argument rests/relies on a speculative chain of events flowing from a single concession.

Example: If we legalize marijuana, then that will lead to all drugs being legal, or any number of political arguments.

Equivocation

Treating two concepts as interchangeable, when really they are distinct

Murphy’s Law

Assuming that because something can fail, then it is bound to fail.