Traditional logic

Disciplines > Argument > Types of reasoning > Traditional logic

Description | Example | Discussion | See also

Description

Start with premises that are assumed to be true. Then use only logical rationale to derive a conclusion. Be careful that it is applied correctly. Keep emotion well out of it.

Example

Say this	Not this
All people have potential. You are a person. You have potential.	Some people have potential. You are a person. You have potential.
Some bananas are yellow. Some bananas are green. I don't know if there are any green and yellow bananas.	Some bananas are yellow. Some bananas are green. Therefore some bananas are green and yellow.
Murder is wrong. Shooting someone dead is murder. Therefore shooting someone dead is wrong.	Shooting someone dead is murder. Murder is wrong. Therefore shooting someone dead is wrong.

Discussion

Traditional logic, as originated by Aristotle, obeys formal rules and is bivalent -- that is, it is about truth and falsehood with nothing in between.

A logical flaw or fallacy is one in which the laws of logic are not followed (irrespective of whether there is real truth there or not). This can often be seen through the use of Set Theory.

An argument that has a logical flaw in it is invalid. A valid argument that is actually true is also sound.

Logical arguments fall down when the premises are false. It is also possible to get snared in a complex logical argument that seems to follow logical rules, but is in fact a fallacy.