Why does IQueryable.All() return true on an empty collection?

Question

So I ran into a situation today where some production code was failing precisely because a method performed exactly as documented in MSDN. Shame on me for not reading the d

Answer 1

It's very similar to the basic concept of the number zero. Even though it represents the existence of absence, it still possesses and represents a value. IQueryable.All() should return true, because it will successfully return all of the members of the collection. It just so happens that if the collection is empty, the function won't return any members, but not because the function couldn't return any members. It was only because there were no members to return. That being said, why should IQueryable.All() have to experience failure due to the lack of support from the collection? It was willing, it was able...it was capable. Sounds to me like the collection couldn't hold up their end of the bargain...

http://mathforum.org/dr.math/faq/faq.divideby0.html