If 'pro' is the opposite of 'con' what is the opposite of 'progress'?The answer that automatically springs to mind is congress and is meant to be a swipe against the legislative branch of most countries; that often really annoying governmental body in which people are supposed to work together to pass legislation, but is often merely a place where partisan politics tend to become magnified (at least it seem so) and that seems like the opposite of what progress is seen to be.
However, while this joke is funny, it's also false (which is - admittedly - part of what makes it funny). And yet - and yet - we have the niggling problem that pro is the opposite of con, right? Well, not quite.
The word pro (as opposed to the prefix) is actually an adverb all by itself that we use today in such Latin-derived phrases, like pro bono or pro tempore (as in "governor pro tem"). According to dictionary.com, the meaning of pro is (to paraphrase) "in favor of/for". In addition, as a prefix, the meaning of pro- can continue to mean "in favor of/for" as well as meaning "advancing forward/projecting". Dictionary.com helpfully provides the antonym of pro- to be anti-. (And here we have the basic problem of the etymological logic behind the quote. The logic is wrong, because the opposite of pro- is anti-, and therefore the opposite of progress - using the strained logic of the joke - is antigress... which doesn't exist as a word.)
Even though we can now see the fault with the underlying logic of the joke, let's move on to the con in "pros and cons", which is actually an abbreviation of contra. This term does mean "against", and therefore fits into a phrasal analogue of "pros and cons" to mean "for and against". However, the etymology of contra is of more interest here, since the joke hinges on the false equivalency of the con- (as a prefix) being the opposite of pro (either as a prefix or as an adverb). The meaning of the prefix con- is "with/together", and is actually the equivalent of the prefix com-, but used in front of hard consonants. Although dictionary.com doesn't provide the antonym for con-, the closest one that comes to mind is dis-, which means "asunder/apart/away" or de-, which means "down/away/reversal".
Therefore, the opposite of con- is dis- and the opposite of pro- is anti-. However, the opposite of congress is not disgress (nor degress), and the opposite of progress is not antigress, because disgress (and degress) and antigress are not words in the English lexicon.
Of course, another problem with the quote is that is assumes that all types of congress is opposite of progress. However, looking at the definitions of congress, there is the definition that means "coitus/sexual congress", and that one might well be progress. Indeed, reading this meaning into the word, we now can construct a new phrase:
Sexual congress can be apposite of progress.Or something like that.