Richard P. Feynman to William Neva, August 14, 1975
Mr. William Neva
Henrietta, New York
Dear Mr. Neva:
Thank you for your letter and for your question about invisibility. I would suggest that the best way to get a good answer to your question is to ask a first-rate professional magician. I do not mean this answer to be facetious or humorous, I am serious. What a magician is very good at is making things appear in an unusual way without violating any physical laws, but by arranging matter in a suitable way. I know of no physical phenomenon such as X-rays, etc., which will create invisibility as you want. Therefore if it is possible at all it will be in accordance with familiar physical phenomenon. That is what a first-rate magician is good for, to create apparently impossible effects from “ordinary” causes.
Richard P. Feynman