A few years ago I was fortunate to attend a lecture given by Paul Wilmott challenging the wisdom of modeling derivatives on the assumption that there is no arbitrage. He floated an alternative approach (as but one of many possible heterodox approaches) outlining the pitfalls therein – chiefly the difficulty of convincing investors to bear with you until your thesis proves out – and toward the end he took questions. Some brave soul asked him, “Where does the money come from?”