Problems of Logic

PROBLEMS OF LOGIC

Problems of logic in proofs include:

• Gaps in the logic: leaping from one statement to another without justifying it, or leaving out too many steps in between.

• Incorrect inferences: this is when a logical step is made that is actually incorrect, where you say something follows logically from something else, but it doesn’t.

• Handwaving: arriving at a conclusion without true use of logic, but by metaphorically waving your hands around enough that people think you are.

• Incorrect logic: subtle fallacies can make an unsupported argument appear valid.

Handwaving often occurs backed up by yelling and insults in arguments in normal life. A comment such as “Anyone with half a brain cell can see this!” may substitute an insult for the missing justification.

An example of an incorrect inference is the view that “scientists agree with each other, which shows there is a conspiracy”. The conclusion (there is a conspiracy) does not follow logically from the fact that people are agreeing with each other, since agreement could also arise from independently examining the same evidence.

An example of a gap in logic is when one person is blamed for something, and all the other factors are ignored. Consider a so-called “swatting” tragedy when a hoax call is made to the police who then storm an innocent person’s home and shoot them dead. If the police often place all the blame on the hoax caller they are leaving out the fact that they shot an innocent person dead with precious little evidence or reason.

An incorrect inference can be subtle. Ask which premises support the conclusion and whether an alternative explanation remains possible.