“Imagination is the only weapon in the war against reality.”
― Lewis Carroll, Alice in Wonderland
I know Alice pretty well, and I am sure that phrase does not appear anywhere in it. But it's always good to check...good old Gutenburg.
And what do you know - the word "imagination" does not appear anywhere in Alice's Adventures in Wonderland or in Through the Looking Glass.
It's interesting that the phrase appears all over the internet - most people believe that it's said by the Cheshire Cat. But it ain't.
So, it's quite a nice phrase - it might even be Lewis Carroll - but it's nothing to do with Alice.