Is there really a difference? I feel like if you don’t know something, that kind of makes you stupid, right? If you don’t know historical facts or mathematics—at least the harder stuff, like algebra or calculus—or if you don’t know about advanced political topics, then you’re kind of a stupid person, not just ‘ignorant.’
Ignorance can be remedied through education. Stupidity, not so much…
That said, most people could be smarter if they were taught to think, but thinking ability is not the same as knowing facts.