Common Flaws

Confusing Necessary and Sufficient

Mistakes a necessary condition for a sufficient one, or vice versa

Numbers, Amounts, and Percentages Error

Draws unsupported conclusions about quantities or proportions

Two Things Are Incompatible, So One Is Wrong

Rejects one theory solely because it conflicts with another assumed to be correct

Allowing a Key Term to Shift in Meaning

Conclusion depends on defining a key term in two different ways

some “term“ is used two diff ways

Strong Conclusions

Draws a conclusion that overstates what the evidence supports

Attributing Knowledge

Assumes someone holds a belief based on a fact the author knows, without evidence of that belief

Only Considering One Reason Against Something

Refutes a claim by addressing only one possible justification for it

Usually ≠ Always

Sometimes ≠ Always

Takes something that typically happens and treats it as a universal rule

Treats a condition that sometimes holds as though it always does

Error Assessing the Force of the Evidence [Unproven vs Proven False]

Some Evidence For → Position is True

Some Evidence Against → Position is False

Lack of Evidence → Position is True

Lack of Evidence → Position is False

Treats evidence showing mere plausibility as if it proves that the conclusion is true

Confuses weakening an argument in support of a given conclusion with proving the conclusion itself to be false

Lack of evidence against a position is taken to prove that the position is true

Assumes a conclusion is false just because the supporting evidence is weak

Parts vs Whole

Assumes that something that is true of the parts is true of the whole, or vice versa

This flaw happens when you look at individual building blocks, and you assume that when you glue them all together, the giant assembled product will have the exact same physical or abstract trait as the tiny blocks.

Mistaken Cause and Effect

Assuming a causal Relationship?

Reversal?

Correlation vs causation?

Alternative Cause?

Assuming? The author assumes that Cause will directly cause the Effect, without showing how or why

Reversal? Mistakes the occurrence of one event after another for proof that the second event is caused by the first. → fails to consider that events may be reversed

Correlation vs causation? Concludes a causal relationship when only correlation exists (pattern viewed), completely ignoring 3rd variable (C) could have caused B OR casued both A and B+ but if causation then can conclude correlation

Alternative Cause? You point out another reason (an alternative cause) for the effect!

Alternative effect or cause?

Circular Reasoning

Assumes as true what is supposed to be proved (aka conclusion), meaning the premise and conclusion are identical in meaning (restates presmise in the conlusion)

Inapporiate Appeal Fallacy - Appeal to Authority/Appeal to Emotion/Appeal to Popular Opinion

Uses the opinion of an authority in attempt to persuade

Appeals to emotion rather than reason

Confuses public opinion with factual reality

Lack of Evidence for the Conclusion Drawn

Conclusion is not warranted by the evidence provided

Internal Contradiction

Claims are inconsistent with each other and/or the overarching conclusion

False Analogy

Treats two different things as if they are similar

Straw Man

Misdescribes an opposing position, thus making it easier to challenge

Source Argument/Ad Hominem

Argument attacks the person (or source) instead of the argument they advance

(dismiss view b/c biased interst/past action)

Relativity Flaw

Information about a relative relationship is used to draw an absolute conclusion, or vice versa

Mistaken Negation

Considers the absence of an occurrence as evidence that a necessary condition for that occurrence also did not take place

Mistaken Reversal

Mistakes being sufficient to achieve a particular outcome for being required to achieve it

Survey Errors

Generalizes from an unrepresentative (or non-random) sample; bases a conclusion on survey responses that were gained through faulty questioning; assumes every polled individual provided a truthful response; etc.

Sunk Cost Fallacy

Justifies future actions on the basis of past actions already committed

Overgeneralization

Bases a broad claim on what could be (an) exceptional case(s) =This is about taking the traits of one member and forcing them onto every other independent member.

eg: If I say, "My friend Bob is 7 feet tall, therefore humans are 7 feet tall," Bob is the exceptional case. I can't use him to make a rule about all humans.

False Dilemma

Assumes that only two courses of action are available when there may be others

Assuming Mutual Exclusivity (Set A and B no overlap) not causal "Thing A made Event B happen," (categories and definitions) "Thing A is X, so it cannot be Y,"

Assumes something cannot belong to two categories. Failed to consider a very simple alternative: Why can't something be BOTH?

There is a gap in the argument

bc a SA need an answer that bridges "You are right, they CANNOT be both!"