I often hear beginning traders speak as if they know what the markets will do next. In reality, experienced traders usually speak in probabilities and typically have some form of analysis to back up their opinion. No one can say that a particular currency pair (or other financial instrument) will move to an exact point with absolute certainty. In fact, I feel it is naive to think that anyone can predict the direction of a currency pair with absolute certainty over a given period of time. Sure, sometimes you could be correct if you boldly predict that a pair will move to X level with absolute certainty. However, there will be other times when the market doesn't go your way. That is why we must deal with probabilities, because no one knows for sure what will happen next in a given currency pair.
The reason we can never know where a currency pair with absolutely certainty is that the markets move based on the will of every market participant. Let's suppose that someone stated "the EUR/USD will definitely rise to point X, before falling down to point Y". They are saying that know exactly what every market participant (or trader) is thinking, how each of these participants plans to act, and how each participant will respond to the actions of every other participant. Needless to say, no one could ever have that information.