''some theory'' vs ''some theories''

Question

I was wondering which one of the two is correct:

• ''he had some interesting theory to share''

or

• ''he had some interesting theories to share''

The latter sounds correct, a friend backed me on that one too, but I'm curious to know why. In this context I'm referring to someone who was putting forth a theory on human nature - as I read it in an article. Technically speaking he only has one theory on HN, not 2 or whatever. Therefore I would like to understand why theory, when put like this, has to be plural because it is kind of misleading I think. Is it just idiomatic?

Thanks a million!

Answer 1

Neither; if he has one theory then I'd suggest:

• "he had an interesting theory to share"

Answer 2

this depends on the context. Since you say it's regarding a scientist (with one theory only) you want to remain "neutral" (not negative) therefore you should choose "an interesting theory"

the other half of your question as to whether "some theory" is an idiom? No, "some theory" is not an idiom.

"some theory/ies" is correct in other contexts, as "some" is a [determiner], or [quantifier] it can be used to modify the meaning of the [countable or uncountable noun]

If you report :

"I saw XY again today. He had some interesting theory to share."

(then we are not sure yet what the theory is but we wait for more info. And it might as well just be an idea or an additional viewpoint)

If you say

"Woa, now that is some theory!" it is either meant approving or disapproving (which can be guessed by the context)

it is not an idiom.

compare: "I talked to some guy(s) at school" (undisclosed, you do not yet specify to whom you talked. ) some= determiner

"I bought some apples" (can't remember how many)