Question: The stack exchange question "Is there any concrete-solid proofs of this space odyssey?" made me want to edit it to remove the s in proofs (someone with enough flair did), however it made me wonder about the plurality of *any* and *proofs*.

So please enlighten me about which one is correct.

> 
> Is there any concrete-solid proof of this space odyssey?  
> 
>  Are there any concrete-solid proofs of this space odyssey?
> 
> 
> 

If the asker wants to hear about at least one proof, the first one is OK, but what is correct if he wants at least two pieces of evidence?

Answer: 
My grammar book (*English Grammar*, David Daniels and Barbara Daniels) reports that the indefinite pronoun *any* is either singular or plural. 

> 
> Someone asked him for a match, but Joe didn't have any.  
> 
>  Do you have any tips to pass on?  
> 
>  I don't have any choice.
> 
> 
> 

In your example, I would use "Is there any concrete-solid proof of this space odyssey?" because if there isn't a single proof, then there aren't two proofs either.
Proof is an uncountable noun. Despite this it would seem it is a common mistake (paticularly in American English) to use "proofs".

> 
> "If the asker wants to hear about at least one proof, the first one is OK, but what is correct if he wants at least two pieces of evidence?"
> 
> 
> 

Proof is both singular and plural, which means whether you want one, two or ten pieces of evidence it's always proof NEVER proofs.

Unfortunately, when people (including academics) make mistakes often enough they become acceptable, so you'll find a lot of examples where proofs is used.

"5 proofs that aliens exist" should read "Proof that aliens exist". If you wanted to use a number it would become "5 ... that prove aliens exist" - truths/facts/examples.

Hope this clears it up.