Are there things "that man was not meant to know"? Of course not. Not meant by whom for a start? Knowledge is good for its practical applications and, in my opinion, is a value in itself. We are
better for knowing, since
1925, that our galaxy is not the entire universe. (I have met people who either disagree with me on that or do not even see the point of such a value judgment.) James Blish's
After Such Knowledge Trilogy
addresses the question whether secular knowledge is evil.
Sometimes an author reaches a limit of what he is able to explain or account for within a given text. Discussing time travel paradoxes, Manse Everard of the Time Patrol breaks off and says:
"'I hope you understand what I'm saying. I don't.'"
-Poul Anderson, The Shield Of Time (New York, July 1991), PART SIX, 18,244 B. C., II, p. 304.
His fellow agent, Komozino, helpfully adds:
"'It requires a metalanguage and metalogic accessible to few intellects...'" (ibid.)
- and besides:
"'We haven't time to quibble about theory.'" (ibid.)
So the text can move on to practical matters! (But one thing that they
do have is
time. Komozino might already have spent weeks, months or years of her lifespan on their current problem. Anderson's characters have come a long way from Wells' Time Traveller and his outer narrator wondering about
curious possibilities of anachronism and of utter confusion.)
When Valgard asks Illrede about the new god, the troll-king replies:
"'Best not speak of mysteries we cannot understand.'"
Indeed, none of us can understand such a mixing of mythologies!
In Neil Gaiman's The Sandman: The Wake (New York, 1997):
"...there are some powers that no one, not even the Endless, seeks to inquire into deeply." (p. 17, panel 4)
Why not?