Testing applicability of economic theories on issues

Whatever economics is, it is not about "I like juice and she likes tea", which says nothing about a third person's preference. To differenciate theoretical conclusions from mere facts, it is probably sufficient to see if it can predict, within a certain scope. As one possible test for presence of predictability, any issue that used to be the subject of a fortune-teller should well be said as predictable. In this aspect, what economists do are not so much different from a fortune-teller. They predict markets, wealth, and give advices on how to prevent certain things from happening. They should be able to compete well with the fortune-tellers and do whatever their competitors can do. At the same time, it would be smart if they consider themselves no more than a fortune-teller, as long as they want to compete with them in predicting, and stay away from other businesses, such as philosophy or wisdom, in which realms the predicting enterprise itself will be questioned.