Please focus on (1).
I think (1) is just ungrammatical, no matter which you choose from among “don’t,” “won’t,” and “should not.”
(1) No problem is so big that you [don’t / won’t / should not] find a solution to it.
cf. No problem is so big that you can’t find a solution to it.
Do you agree?
Thank you in advance
Seiichi MYOGA
I think “won’t” works. The implication is “if you look long or hard enough.”
Any of the variations of (1) is perfectly grammatical.
“No problem is so big that you don’t find a solution to it.” = Mister, you find a solution to any problem, no matter how big it is!
“No problem is so big that you won’t find a solution to it.” = Mister, you’re so good at solving problems that you’ll find a solution to any problem, no matter how big it is!
“No problem is so big that you shouldn’t find a solution to it.” = You shouldn’t ignore problems or be intimidated by them. No matter how big they are, you should find some kind of solution.
All of the variations are perfectly grammatical.
Dear Barb_D and Jamie (K),
I appreciate your help and comments.
Unfortunately and regrettably, we don’t learn what kind of cognition our choice of a modal in an embedded clause (as in “Work hard so that you [may/can/should/will] pass the test.” corresponds to. So we tend to fool ourselves that the resulting differences in meaning can be small enough to ignore.
Thank you
Seiichi MYOGA