"What is grand is necessarily obscure to weak men. That which can be made explicit to the idiot is not worth my care." -- William Blake
"[If a physical theory cannot be explained to a child, it is probably worthless]." -- Albert Einstein
Obviously, different situations. One is poetic truth, one scientific. Plus, granted, you could argue that it is easier to explain something to a child than to an idiot, if you imagine the difference is that children are more open minded. And Einstein, not being a crazy prophet, tossed in the qualifier "probably". But if you only had to chose one to live by, which one would you go with? I can never decide and just go back and forth as the mood strikes me. Alternate Question: which quote covers your most recent mood.
[I cannot find the exact Albert Einstein quotation -- only a paraphrase. Let me know if you know it.]