Indeed, there are a few contributors here who follow the previously quoted advice of Cicero to the letter.
When in Rome... (Actually, I was just making a general observation based on the tenor of the exchanges in this thread. Do you feel singled out by that remark? If so, that would be an interesting inference on your part. Cognizance of guilt, perhaps?)
By having a positive expectation. If I have a biased coin that flips heads 51%, then I can make money even though I have no idea whether the next flip is going to be heads or tails. Price can move massively in the wrong direction many times during the lifetime of your trading system (or even career), or even the *majority* of the time you trade, and yet you can still make net long run profits despite this fact. To be profitable, a system only needs to antipate the distribution of possible future price movements more accurately than the market.
A subset of a category does not define the entire category. Trend-following approaches exist, which do not use the prior existence of a trend as their sole signal. Therefore, proving that using this sole signal is not profitable does not prove that trend-following is not profitable. In any case, performance data from the past couple of decades shows us funds which *do* use only that single signal of a prior trend existing, and have been profitable. If you were correct, they should have made zero, minus their transactions costs, minus the inherent negative edge which comes from trading with a stop. Instead, they made profits - how do you reconcile this with your claim? Have you made a significance test on their results to work out what kind of confidence level is implied by their returns?
You can't be serious. What you have done is merely substitute expectation for anticipation and agree with me.
Expectation is not the same as anticipation though, is it? A trend-follower doesn't have to be any good at predicting if a trend will continue. All they have to do is trade in a way such that the profits that accrue when the trend continues are higher than the losses they suffer during reversals and market chop. They don't have to predict price, merely the likely distribution of prices.
In my experience, trend-following in the minutes following a major piece of market-sensitive surprise news has the highest win ratio. Good examples would include the Spitzer lawsuit against MMC, the European stock index futures on 9/11, the "reverse crash" after the surprise inter-meeting fed rate cut in autumn 1998, and so on. On a smaller timescale, trading the reaction to out-of-line major economic figures such as non-farm payrolls is another trend-following approach with a good win-rate.