That problem is undecidable and bubble is not well defined[1], but you only have to look at the price of gold to see that there's evidence for a claim that gold is in a bubble.<p>Certainly the idea that gold is immune to inflation, overvalue or a bubble is entirely absurd and outright dangerous to the people who might fall into the trap of believing it.<p>[1] If someone had such an algorithm Wall Street financial firms would be making untold amounts of money off of it, most trading algorithms are just rough heuristics that happen to work, but rarely work for extensive periods of time or any specific claims.