Pop quiz: what’s the difference between a bag and a sack? For some amusing answers, check out this post by Allan Metcalf. The bottom line, though, is that no one agrees. Because, in my humble opinion (along with Dr. Metcalf and five of his students), they’re just synonyms. So why do we invent differences between words that actually mean the same thing?

Just as nature hates a vacuum, so language hates synonyms.

To be precise, it’s the users of language who hate exact synonyms. After all, common sense and our experience of language tell us that if there are two different words, they must refer to two different things. So when two words seem to refer to the same thing, we are inclined to invent a difference.

It all boils down to the fact that we like to rationalize things. We like nice, orderly worlds with nice, orderly words.

But sometimes a synonym is just a synonym.