Invaluable Invulnerable

If I said to you that your contributions have been invaluable, you’d have a sense that I thought your work was worth quite a lot.

If I was an alien looking in from outer space, trying desperately to understand human speech and the English language, I might reasonably postulate a thesis: that putting in- in front of a word amplifies that word. In + valuable equals very valuable, essentially.

If I applied this thesis to the word invulnerable, I’d be in for a rude awakening (do aliens have rude awakenings too?). In + vulnerable should mean that you’re very vulnerable, right?

Unfortunately for people who appreciate simplicity (like virtually anyone trying to learn grammar), the opposite is true here. What’s going on?

In the case of in-, it seems like valuable is amplified in invaluable. That in- does a lot of heavy lifting at the start of that word! Unfortunately for lovers of this word, there’s another far more common meaning for the in- prefix.

The word invulnerable runs with this version. In this case, in- is a negator instead of an amplifier, and you’re saying something isn’t vulnerable at all. While invulnerable means not-at-all-vulnerable, invaluable’s in- seems to indicate the opposite—that something is very valuable.

Do we really have to live with this duality? Not necessarily. Let’s zoom in for a sec to see how.

Invaluable as a word came about because there was already a word for something that has no value: valueless. A little creative interpreting led down this pathway: value can’t really be put on something that’s this important.

Another good word for this is priceless, although we can debate price and value some other time.

So, in- isn’t really an amplifier here at all—it’s a negator, just with a little clever hoop-jumping to get there.