In William Shakespeare's Hamlet, Act 4, Scene 5, the line "We know what we are, but know not what we may be" is spoken by Ophelia to Claudius. She suffered the loss (death) of a parent. She is now trying to give her life some kind of perspective.

Man is often said to live in the moment. We may guess about it: 'we know what we are.' We think basically that we know that we are all human. We may know about our outer limits. The 'but not what we may be' could mean that we are not sure of what we will become in the future, even if some of us have clear plans of what we want to be. All we know is the person we used to be in the past, and the one that we are today. We cannot foresee the future. We cannot predict the obstacles we will face or imagine the people we will meet. Thus we cannot fathom the person we will become as a result of these experiences and encounters.

Metaphorically, you stand at the dock before the vast ocean. It means that you know where you currently are, but have no idea of what exactly is to become of you.

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