Why not say supply and demand? We can talk about the fundamental reasons all day long but it's the buying and selling pressure that moves the price of any market, be it the long or short term.
Because that's too glib for beginners, most of whom think that there's some connection between the value of a stock and the value of a company. To answer the OP's question with "demand" wouldn't have meant much.
Yes indeed..perception,which equals expectations ,is a very strong catalyst(positive earning suprise ),but ultimately EPS has the final say. P.s. it appears that most are looking at growth stocks,so I intentionally didn't bring up asset plays,turnarounds,value investing. If you want an objective overview,look at AAII /Portfolio123/Validea and see which methodology produced the best returns.
I have no idea. Im only concerned with making money from these things known as markets. In fact, im quite obsessed with that.