I heard someone say “inversely” yesterday to introduce a contrary opinion to what he first stated.

Problem:
The adverbs “inversely” and “conversely” are not synonyms, just as the adjectives “inverse” and “converse” are not synonyms.

Explanation:
When I heard someone yesterday state one opinion and then introduce an opposing opinion with the adverb “inversely”, I thought that it sounded odd.

I was expecting him to say “conversely” instead of “inversely”, so I decided to learn more about the adjectives “inverse” and “converse”.

This adjective “inverse” dates back to around 1610 from a Latin verb that means to turn inside out or upside down.

So an example of valid use of the adjective “inverse” is “The inverse form of the fraction 3/4 is the fraction 4/3.”

The adjective “converse” dates back to the second half of the 1300s from a Latin verb that means to turn around.

So an example of a valid use of the adjective “converse” is “The converse perspective to ‘The glass is half-full.’ is ‘The glass is half-empty.'”

It may help to look at the words “inverse” and “converse” when they are used as nouns in mathematics.

Given the statement “if p, then q”:

• “if not p, then not q” is the inverse;
• “if q, then p” is the converse.

Notice how the inverse “turns inside out” the original statement and how the converse “turns around” the original statement.

Solution:
Use the adjective “inverse” to label something that is upside down or inside out. Use the adjective “converse” to label something that is contrary or turned around.