Quantum theory is like a drug

I am in Oxford for a conference Quantum Physics and the Nature of Reality, in honour of the 80th Birthday of Sir John Polkinghorne.

Here is some of the last two paragraphs of Polkinghorne's book Quantum Theory: A very short introduction.

It seems appropriate to close this chapter with an intellectual health warning. Quantum theory is certainly strange and surprising, but it is not so odd that according to it `anything goes.' Of course, no one would actually argue with such crudity, but there is a kind of discourse that can come perilously close to adopting that caricature attitude. One might call it `quantum hype.' I want to suggest that sobriety is in order when making an appeal to quantum insight.

..... Wave/particle duality is a highly surprising and instructive phenomenon, whose seemingly paradoxical character has been resolved for us by the insights of quantum field theory. It does not, however, afford us a license to indulge in embracing any pair of apparently contradictory notions that take our fancy. Like a powerful drug, quantum theory is wonderful when applied correctly, disastrous when abused and misapplied.

The cartoon is from xkcd.