Grantham asked a group of mathematicians how big Ancient Eqypt would have gotten if its economy had growth 4.5% a year for the 3,000 years the civilization lasted.

The mathematicians were directionally correct: Very big.

But not one of them came even remotely close to the actual number (which is mind-boggling).

I posted on @Quora: Here's Why Our Long-Term Growth Expectations Are Absurd http://qr.ae/7Xjhm #Math #Business