The following are Fallacies which you may wish to avoid when engaged in argument. These are put here because they can help you better sculpt your argument, and avoid saying what you wish not to say.
These are not rules for posting here, nor will they be enforced. Instead, they are suggested in the hope that the creativity and skill of argument can flourish rather than stumble and burst into flames.
Logical Fallacies to avoid in discussion or debate:
Post Hoc Ergo Proptor Hoc or “After this, therefore because of this” – a logical fallacy in which one assumes that because something occurred after a prior event, that it was caused by that event.
Example:
The sky starts brightening in the east, then the sun rises, thus causing a great fool to assume that the sky’s brightening is what caused the sun to rise.
Argumentum ad hominem or “Argument against the person” – a logical fallacy which consists of countering an point by attacking the person presenting the case rather than the actual point.
Example:
John: The sky is blue.
James: John is a (insert your choice of pejorative term here.)
Affirming the consequent – a logical fallacy in which one assumes that the reverse of an argument is true, generally occurring with a statement consisting of a cause and effect, asserting that the truthfulness of the effect implies the veracity of the cause.
Example:
Humans are mortal.
Bear is mortal.
Bear must be human. (actually, that’s my pet Labrador.)
Appeal to authority – a logical fallacy in which the veracity of a statement is supported only by authority of the one that said (or wrote) it.
Example:
John makes a statement.
John is an expert in the field to which the statement pertains.
Therefore, the statement must be true.
Argumentum ad populum – is a logical fallacy in which a statement is assumed true because a majority of people believe it true.
Example:
Most people believe the earth is flat.
Therefore, the earth is flat.
Argumentum ad ignorantiam is a logical fallacy in which a statement is assumed valid because there is no evidence of it being false or conversely, that it is false only because it has not been proven true.
Example:
There is no evidence that there is extraterrestrial life. Therefore, there is no extraterrestrial life.
Cum hoc ergo proptor hoc – a logical fallacy in which one assumes that because event A and B occur together, one must have caused the other.
Example:
CO2 levels and crime have both risen since the 1950s.
Therefore CO2 causes crime.
False dilemma – a logical fallacy in which two alternative points of view are the only considered options, exclusive of other possibilities not considered.
Example:
Bob voted against my crime bill. Therefore he must be against law enforcement.
Secundum quid – a logical fallacy in which one jumps to a conclusion based on insufficient information.
Example:
I like Stilton, therefore I will like all blue cheeses. (ignoring the fact that Gorgonzola tastes nothing like Stilton.)
Red Herring – a logical fallacy in which one deliberately attempts to distract from the actual point.
Example:
The Lewinski scandal.
Straw man – a logical fallacy in which one intentionally misrepresents an opponent’s position. To set up a “Straw man” argument is to create a position that is easy to refute, then assign that position to an opponent. Though this technique can be convincing, it is misleading as it does not address the opponent’s actual position.
Example:
A: I think War Games was a better movie than Tron.
B: Why do you insist on berating Tron?
If you can think of more (and I am certain there are), let me know and I will include them to this list.
Thanks to
Cofaidh for bringing these to my attention and suggesting they be stickied. It has been a long time since I took Ethics, I had forgotten some of these.
Have fun.
Thanks!