under which circumstance would you conclude that you have been wrong?
I think I already answered that earlier today or yesterday...
Can you describe what would qualify as: a) a "success" of Bitcoin
I will be happy, and count it as a success, if bitcoin becomes a viable and attractive alternative to credit cards for legal international payments via internet. By "attractve" I mean one that many people will chose to use for its merits (convenience, price, safety, etc.), not for political motives or because they have invested in Bitcoins and want to encourage merchants.
Right now it is very far from that landmark, wouldn't you agree? Already I know that I will not be able to pay a hotel bill in China, for example.
b) Bitcoin being a good investment.
Buying a lottery ticket is always a bad investment, because one can compute the expected payoff, and it is negative.
If one buys a ticket and wins the jackpot,
still was a bad investment.
A good investment is one that, according to the best knowledge and judgement available at the time, gives a positive expectation of return. But there is no way to measure the probability of an event, either before or after the fact. Therefore, there is no way to determine empirically that something is a good investment before the fact, and no way to tell whether if it was a good investment after the fact.
Only in very few cases cases --- such as lotteries and other games --- there are proabilities that everyone would agree to, and therefore one can "prove" that something is a bad or good investment. Most of the time, probablities are subjective and personal, and so is the notion of "good investment" or "bad investment".
If someone invests in Bitcoin and gets filthy rich, good for him; but can you tell whether he was wise, or just lucky but stupid?
Last year the Brazilian oil company OGX filed for bankruptcy. Its stock price had multiplied by 10x in a couple of years (from 2 BRL to 24 BRL, if I recall correctly), which is fantastic in that market. Then it crashed in a few days, after it became known that its two deep-sea oil wells were nowhere as productive as it was hoped. Its shares are still traded today as a penny stock, 0,15 BRL in november, 0.30 BRL now.
OGX had several billion dollars of real money invested into it by many people. Were those people bad investors? I would not say so, they apparently did their homework and got positive expected value at the time.
Some of the original investors must have sold at the peak and made 1000% profit, some didn't and had 100% loss. Were the former better investors than the latter?
Or, to be more dramatic -- someone plays Russian Roulette ten times for a 10$ bet, and wins. Would you call that person a good investor?
(That reminds me of a great little movie called /Number 13/ -- not to be confused with /Number 23/. But I saw the French BW original, cannot vouch for the remake.)