"Oh, you can’t help that," said the Cat: "we’re all mad here. I’m mad. You’re mad."
"How do you know I’m mad?" said Alice.
"You must be," said the Cat, "or you wouldn’t have come here.”
I also wonder what was going on in his head when he worked on his most famous work, the Garden of Earthly Delights
This painting is full to bursting with symbolism, was Bosch troubled, tormented or simply philosophical?
I must say, I do not really understand this work and therefore I can make no intelligent attempt to explain it. Dr Sally Hickson in her article: Bosch, The Garden of Earthly Delights uses the above lines from Lewis Carroll's Alice in Wonderland to suggest madness, indeed Bosch's world does appear to be the world of the insane. Hickson writes
"Bosch’s" mind might be distracted with thoughts of lust, symbolized by the bagpipe-like instrument balanced on his
head which is a standard phallic symbol"
Using Carroll is rather a clever allegory I think, if you consider the feelings Carroll is said to have had towards Alice Liddell.
Interestingly some of Bosch's surviving works has been a subject of debate. Bosch signed only seven of his paintings, there is uncertainty whether all the paintings were actually by him. Many copies of his paintings began to circulate during the sixteenth century and today art historians have suggested that many of the works once thought to be his, are in fact, not. It is said that he painted twenty five of the many attributed to him.