Summary

A general rule is applied when circumstances suggest that an exception to the rule should apply.

Examples

1. The law says that you should not travel faster than 50 kph, thus even though your father could not breathe, you should not have travelled faster than 50 kph.
2. It is good to return things you have borrowed. Therefore, you should return this automatic rifle from the madman you borrowed it from. (Adapted from Plato's Republic, Book I).

Proof

Identify the generalization in question and show that it is not a universal generalization. Then show that the circumstances of this case suggest that the generalization ought not to apply.