Recap
Flaws in a line of reasoning may render an argument specious or illogical. An illogical argument has a conclusion that does not follow from its premises. A specious one looks plausible but depends on a gap, a trick or a shortcut. Names such as hasty generalisation or false cause are shorthand; credit comes from explaining what is wrong in the particular argument.
Common flaws
| Flaw | What is wrong |
|---|---|
| Hasty generalisation | Too few or unrepresentative cases for a broad claim |
| False cause | Sequence treated as cause |
| False dilemma | Only two options offered when more exist |
| Slippery slope | A chain of consequences asserted, not shown |
| Straw man | Opponent’s view distorted |
| Ad hominem | Attacks the person, not the argument |
| Circular reasoning | The claim is used as its own support |
| Red herring | Irrelevant point diverts attention |
| Faulty analogy | The comparison differs in a relevant way |
| Non sequitur | The conclusion does not follow |
| Irrelevant authority | Expertise outside the field |
| Bandwagon | Popularity treated as proof |
| Overstating | The conclusion outruns the evidence |
Questions that expose flaws
- Is the evidence enough?
- Does the conclusion follow?
- Is there a rival explanation?
- Are only two options given?
- Is the opponent’s view fair?
- Is the attack on the argument or the person?
- Is each point relevant?
- Are the consequences shown or asserted?
- Is the comparison really parallel?
Repairs
- Narrow the claim or add representative evidence.
- Add evidence of a cause or rule out others.
- Acknowledge other options.
- Show each step of a chain or limit the claim.
- State the opposing view fairly.
- Answer the argument, not the person.
- Provide independent reasons.
Worked mini-example
“Since the new head arrived, attendance has fallen. So she is clearly the cause. Either we remove her or attendance will fall for ever.” Flaws: false cause (sequence is not cause; other explanations exist) and false dilemma (only two options offered). Repair: note the coincident flu outbreak and bus cuts, and propose comparing routes and absence reasons before attributing a cause.
Swift, “A Modest Proposal” (1729): the narrator’s “let no man talk to me of other expedients” closes off alternatives, a deliberate false dilemma. The flaw is the point: satire exposes the premises behind real policies.
Mistakes to avoid
- Naming a fallacy and not explaining it.
- Calling every emotional appeal a fallacy.
- Assuming a true conclusion means sound reasoning.
- Rejecting a whole argument because of one repairable flaw.
- Missing deliberate flaws in satire.
- Using the flaws in your own writing.
Quick self-check
- What is a false cause? Assuming that because B followed A, A caused B.
- What is a straw man? Distorting an opponent’s view so it is easier to attack.
- What is the difference between specious and illogical? Specious: looks sound but misleads; illogical: the conclusion does not follow.
- Why might a satirist use flawed reasoning deliberately? To expose the premises behind a real policy or attitude.
- How do you repair a hasty generalisation? Narrow the claim or add representative evidence.
For the full explanation and worked examples, return to the study guide.