"Not sure I'm following the logic.  You need a single prediction market, or rather, you have as many Science!s as there are prediction markets.  But a single worldwide prediction market follows automatically from 'arbitrage' - if one market is buying a proposition at 80% and one market is selling at 60%, you can buy in the 60% market and sell in the 80% market and make a guaranteed profit and do that until the prices equalize."

"Not sure I'm following the logic.  You need a single market for predictions, or rather, you'd expect to end up with as many separate Science!s as there are separate markets.  But a single worldwide market follows automatically from 'arbitrage' - if one market is buying a proposition at 80% and one market is selling at 60%, you can buy in the 60% market and sell in the 80% market and make a guaranteed profit and do that until the prices equalize."

"Not sure I'm following the logic behind the question?  You need a single market for predictions, or rather, you'd expect to end up with as many separate Science!s as there are separate markets.  But a single worldwide market follows automatically from 'arbitrage' - if one market is buying a proposition at 80% and one market is selling at 60%, you can buy in the 60% market and sell in the 80% market and make a guaranteed profit and do that until the prices equalize."