Friedman continues, but I shortened the quote to make it punchier. Essentially he says that, (1) given a large number of individuals irrationality will average out in the aggregate,
This is the part that sounds (and is) wrong. It would perhaps be correct if it was “given a large number of individuals selected from mind space via a carefully crafted distribution of deviations about some mind the irrationality will average out in the aggregate”. The irrationality of a large number of human individuals will not average out.
This seems to be an argument about definitions. To me, Friedman’s “average out” means a measurable change in a consistent direction, e.g. significant numbers of random individuals investing in gold. So, given some agents acting in random directions mixed with other agents acting in the same (rational) direction, you can safely ignore the random ones. (He argued.) I don’t think he meant to imply that in the aggregate people are rational. But even in the simplified problem-space in which it appears to make sense, Friedman’s basic conclusion, that markets are rational (or ‘efficient’), has been largely abandoned since the mid 1980s. Reality is more complex.
This is the part that sounds (and is) wrong. It would perhaps be correct if it was “given a large number of individuals selected from mind space via a carefully crafted distribution of deviations about some mind the irrationality will average out in the aggregate”. The irrationality of a large number of human individuals will not average out.
This seems to be an argument about definitions. To me, Friedman’s “average out” means a measurable change in a consistent direction, e.g. significant numbers of random individuals investing in gold. So, given some agents acting in random directions mixed with other agents acting in the same (rational) direction, you can safely ignore the random ones. (He argued.) I don’t think he meant to imply that in the aggregate people are rational. But even in the simplified problem-space in which it appears to make sense, Friedman’s basic conclusion, that markets are rational (or ‘efficient’), has been largely abandoned since the mid 1980s. Reality is more complex.