Explanation

A sweeping generalisation applies a general statement too broadly. If one takes a general rule, and applies it to a case to which, due to the specific features of the case, the rule does not apply, then one commits the sweeping generalisation fallacy. This fallacy is the reverse of a hasty generalisation, which infers a general rule from a specific case.

Example

(1) Children should be seen and not heard.
(2) Little Wolfgang Amadeus is a child.
Therefore:
(3) Little Wolfgang Amadeus shouldn’t be heard.

No matter what you think of the general principle that children should be seen and not heard, a child prodigy pianist about to perform is worth listening to; the general principle doesn’t apply.