If someone breaks into my house and steals my TV, they might explain that they needed a new TV since theirs broke. That would be an explanation for why they did what they did. But it wouldn’t be an excuse, because they could have done other things as well like not stealing my TV.
The idea is that we can understand why someone does something but still acknowledge that what they did was wrong and they shouldn’t have done that in the first place.
Latest Answers