We have an old adage: Buy Low and Sell High.
Yet, we can never say what the actual Low is? Therefore, if you, the trader believe that prices are likely to go higher then the current price is a Low.
This is a recurrent theme in many of my CNBC Investor Camp presentations.
Now, we can never know with certainty if prices will go up in the future. Therefore, we, traders, rely on probability.
Think about it.