A correspondent writes to ask about the use of the unpremodified quantifier many in affirmative sentences. He says: 'When I venture to use many affirmatively, the result sounds awfully unnatural: I’ve seen many fish while I was snorkelling, I’ve seen many hybrid cars in Wellington. Other examples that puzzle me include: I’ve interviewed many people (which I think sounds natural) vs I’ve eaten many biscuits (which is an example that Geoffrey Pullum singles out as particularly objectionable).' And he adds: 'Does many actually refer to a different number from a lot of?'
I think we're dealing with a stylistic issue here. Many has long had an association with formality, as also, incidentally, has few and much. It's always difficult to pinpoint the origins of a stylistic preference, but I think this one is due to biblical influence, especially via the King James Bible, where we find many examples:
many are the afflictions of the righteous
a father of many nations
a coat of many colours
many are called but few are chosen
It also appears a lot in proverbs, such as Many hands make light work. And it became a feature of high-blown rhetorical style: Many would agree with me....
The stylistic contrast is easy to demonstrate. Take the sentence I used just now. Replacing many produces an immediate informal tone:
...where we find many examples.
...where we find a lot of examples.
...where we find lots of examples.
Conversely, when many is used, the collocations ought to satisfy the demands of that stylistic level, otherwise they will seem anomalous. This, I suspect, is why Geoff Pullum doesn't like many biscuits, and why many hybrid cars and many fish in the context of snorkelling sound odd. These notions are perhaps a mite too downmarket for an upmarket quantifier, as would be many hiccups, many flutters (on the races), and so on, where one of the lot constructions would be the usual quantifier. As always, we should try to find convincing contrasts:
Many people were waiting to enter the building.
?Many guys were waiting to enter the building.
But the situation is fluid, because there is a far more flexible use of many in negative constructions and when modified (how many etc). So I'd expect there to be quite a bit of opinion difference about this, and probably quite a bit of regional difference too.