I assume you mean "Twain", not "Twian".
Yes, it is Twain, not Twian. Thank you for pointing that.
Please click on "Eve's diary" in the first post to take you to the whole story. Then search the page for I don't know ... and it should take you to the sentence.
Thank you for trying to help.
Edit: This is the wole paragraph.
Some things you CAN'T find out; but you will never know you can't by guessing and supposing: no, you have to be patient and go on experimenting until you find out that you can't find out. And it is delightful to have it that way, it makes the world so interesting. If there wasn't anything to find out, it would be dull. Even trying to find out and not finding out is just as interesting as trying to find out and finding out, and I don't know but more so. The secret of the water was a treasure until I GOT it; then the excitement all went away, and I recognized a sense of loss.