Postdiluvian doesn't seem a particularly useful word. Antediluvian is nice bit of hyperbole to say something is old fashioned.
Somewhere I read that when seashell fossils were found in the Alps, the Bible-bangers claimed that proved the Flood had really covered the whole world!

It's a useful word if you are a Christian, since there are some significant things that changed after the Flood that are useful to remember.

bang bang!

Even if you're not a Chriation there might have been a big flood in your area that wreaked some serious damage. You may want to refer to things that happened before it and after it.

Apres nous le deluge!

Chriation

Huh? Help me out here...

Chriation

Its a concatenation of Christian and Creation.

Apres nous le deluge!

Gosh! I do hope not, dear doctor. But with (maybe) global warming, you could be prophetic here I suppose.

Dear dxb: I was not trying to be prophetic, just trying to dig up a quate about floods:
"Thus did Louis XVI the King of France and husband of Marie Antoinette live to witness his subjects write Article 11 into their “Declaration of the Rights of Men” in 1791 whereby “the unrestrained communication of opinion being one of the most precious rights of man, every citizen may speak, write and public freely” leaving the King to say , “Apres nous le deluge,” before he lost his head a year later."

I had to do my RS (religious studies) GCSE exam today (national tests at age 15/16), which is compulsory in my school as it's CofE and I just couldn't resist using antedeluvian - I couldn't quite find a context for postdeluvian. I'm not overly chuffed at being made to do RS as the curriculum is so limiting over here so I just do what I can to make the exam fun by adding in extra essays and stuff - my RS teacher once accused me of being too(!) philosophical in my essays - maybe that'll stump them... (perhaps not?)
My friends think I'm crazy.

I'd always heard "apres nous le deluge" attributed to Mme de Pompadour, mistress of Louis XV.

Bingley

Dear Bingley: I too thought it was attributed to Madame Pompadour, who had more brains than Louis XVI. I just happened to find it attributed to Louie Blooie in what seemed a scholarly article. You can find it attributed to bothe sources.
Incidentally, "brains" is a brainless phrase, isn't it?

"brains" is a brainless phrase, isn't it?


Perhaps "brains" is slang in referring to intelligence, but it would be perfectly fine in a sentence such as:

The soldier's boots were spattered with blood and brains.