I.E. Does Not Mean 'For Example'

Are these the whole set or just examples?

This is another pet peeve.  I seem to have a few.

The abbreviation 'i.e.' is short for a Latin phrase that means 'that is', NOT 'for example'.

THE CORRECT ABBREVIATION FOR 'FOR EXAMPLE' IS 'E.G.'

'I.e.' stands for id est, which is Latin for 'that is'.  Pretty straight forward.

'E.g.' stands for exempli gratia, which is Latin for 'for the sake of example', from the noun exemplum ('example') and the preposition gratia ('for the sake of'), actual word endings depending on what case you're using; e.g., nominative, genitive, etc., and number; i.e, singular or plural.

I know: TMI. Don't worry about case and number; you don't want to go there.

Zeus as Jupiter Being Pissed

The point is, these two abbreviations are not interchangeable because they mean different things.  You can't use i.e. and etc. together ( 'etc' stands for et cetera, which is Latin for 'and so on') due to the meaning of i.e.  So if you find yourself wanting to use 'etc.' in a sentence, you'd better not also be using i.e., or Zeus will be pissed.

So technically, why are i.e. (that is) and e.g. (for example) different?  Simple.

'That is' means 'in other words', so you're describing the same thing, but you're just using different words to describe it.  For example, "That player really blew it; that is (i.e.), he had the lead, but grew over-confident and lost the match."  Different words to express the same thought.

'For example' means you're identifying just one member, or perhaps a few members of a set of things, as representatives of that set.  Here's an example: "A rainbow consists of a number of primary colors; e.g., red, blue, etc."  Red and blue are members of the set of primary colors in the rainbow.

If you list all the colors of the rainbow, then e.g. is inappropriate.  That's the job for 'i.e.'  So if all the primary colors in the rainbow were just three; i.e., red, blue and yellow, you should use i.e. when you name them all, because the nature of i.e. (that is) requires you to list ALL members of the set.  Remember, the rule is that it indicates 'sameness' but described with different words.

'E.g' requires naming fewer members than exist in the entire set, because you are defining 'representatives', i.e., 'members' of the set in your 'for example' statement.