E.g. currently (May 24 2012) there is uncertainty regarding whether Greece will leave the EU and if so, what effect this will have on the EU, and how this will effect the world economy and various indicies of stock prices.
If you watch the price of the S&P 500, the FTSE, the EUR/USD exchange rate, the GREK stock ETF, and the VIX indicator over the past few weeks, on average over longer periods of time they seem to all "care" about the Greece/EU situation. And, on shorter periods of time, they tend to treat news on that in similar ways (e.g. more chance that Greece will exit -> stock markets down, EUR/USD down, VIX up), but not always -- sometimes some of them will go the opposite upon news. However, on medium periods of time, they often move in opposite directions to each other.
A simple interpretation is that these are also measuring other things besides Greece. E.g. the S&P 500 is also reacting to sunny U.S. corporate earnings and real estate reports.
Another factor is endogenous dynamics. E.g. after the S&P 500 dropped for a number of days in a row, it "wanted" very badly to go up at least a little.
However, I'd like to explore another possible factor. Perhaps these indicators are, to a larger extent than it seems, tracking the Greece/EU situation, however, perhaps they are revealing inconsistent beliefs in the mind of Mr. Market.
Which would mean that the financial markets, considered as a cognitive system, might provide inspiration for a new paraconsistent logic (or, perhaps a model of the markets would turn out to be homomorphic to a known paraconsistent logic).