What is an excuse exactly?

When you act wrongly, you incur a debt of sorts. Show up late to your girlfriend's surprise birthday party, for example, and you will owe her an apology — and maybe a drink.

When you make an excuse, Sliwa said, you are negotiating the size of that debt. If you tell your girlfriend that you were late because you forgot her gift and had to go back for it, you might owe her less of an apology.

A good excuse minimizes how much you owe to the person you wronged. But even the best excuse won’t erase the debt. It will only diminish it.

“Maybe you don't owe the person a drink,” Sliwa said. “But you don't get off the hook entirely. You will always owe something.” She added, "You still have to give a heartfelt, ‘I'm sorry.’”

What makes for a good excuse?

Sliwa said that good excuses show you had the right intentions. In other words, you can minimize the debt you owe by demonstrating that you meant well.

If you tell your girlfriend that you would have shown up on time if you had not forgotten your phone, you make clear that you intended to do right by her. You still have to apologize for being late, but you don’t have to apologize for being inconsiderate.

If you tell your girlfriend that you were late because you wanted to watch "Stranger Things," you make clear that you don’t care about her. You have to apologize for your being late and also for being rude.

What have other philosophers said about excuses?

Sliwa's insight about good intentions may sound obvious, but it runs contrary to centuries of philosophy.

Eighteenth-century Scottish philosopher David Hume said that a good excuse is one that shows that you typically do the right thing. Imagine that you lie to your girlfriend about what you were doing after work, and when she finds out, you say that it’s not a big deal because normally you don’t lie.

Hume would say that’s a fine excuse. Sliwa isn’t buying it.

“I think that’s just mistaken,” she said. “If you say, ‘I might have been dishonest in this particular case, but I'm generally an honest person,’ that’s not going to get you anywhere.”

Twenty-first-century American philosopher Jay Wallace, on the other hand, said that a good excuse shows that you did nothing wrong. You lie to your girlfriend about where you went after work, for instance, and when she finds out that you lied, you say that you were shopping for her birthday gift.

Sliwa disagrees with this view as well. She said that what Wallace is describing isn’t an excuse. It's justification. Since you did nothing wrong, you did not incur a debt, so there is nothing to negotiate. You do not need an excuse.

What about those times when you don't have an excuse?

Whether you think about excuses like Hume or Wallace or Sliwa, there are going to be times when there is nothing you can say to make up for your wrongdoing.

In that case, Sliwa said, don't try to make an excuse. Just say you're sorry.

“You could just acknowledge that you didn't act as you should have, and then apologize for it and express your remorse, and compensate the other person and then move on," she said.

“I think that sometimes it's just not worth it to negotiate," she added. "Sometimes it's worth it to pay the full price and move on with it."