What are logical fallacies?
Logical fallacies are flaws in reasoning that make an argument invalid. They can be either formal or informal.
- Formal Fallacies: These are fallacies that can be identified by examining the logical structure of an argument. They occur when the conclusion does not follow logically from the premises. An example is “affirming the consequent,” where someone claims that if one thing leads to another, then that second thing must necessarily mean the first thing occurred. For example: If it rains, the street will be wet. The street is wet. Therefore, it must have rained. (The street could also be wet for other reasons, such as a sprinkler system or a spilled bucket of water.)
- Informal Fallacies: These are errors in reasoning that involve the content of the argument, rather than its structure. They often involve misuse of language or some form of deception. There are many types of informal fallacies, including:
- Ad hominem: Attacking the character of a person making an argument rather than the argument itself.
- Appeal to authority: Claiming something is true because an unqualified or irrelevant ‘authority’ says it.
- Straw man: Misrepresenting an opponent’s argument in order to make it easier to attack.
- Red herring: Introducing an irrelevant point to divert attention from the subject of the argument.
- False cause (post hoc ergo propter hoc): Assuming that because B follows A, A must cause B.
Fallacies can be persuasive and are often used intentionally in politics, advertising and debate to sway the audience’s opinion. Understanding these logical fallacies can improve critical thinking skills and help in recognising when an argument is flawed.