Gold fell by $600 an ounce over the subsequent 2½ years. That alone inclines me to pay close attention to what he is now saying about Bitcoin. This cryptocurrency has been on a tear of late, with a year-to-date gain of 170%. In recent days, in fact, Bitcoin has risen to new all-time highs, eclipsing its prior high set in late 2017. The valuation framework that concludes Bitcoin’s fair price is about $12,000 is based on the thesis that its value derives from what’s known as a “network effect.” That is, a network’s value grows faster than the number of connected users. (This framework is related to what’s known as Metcalfe’s Law, which holds that a network’s value grows according to the square of the number of users.)