In Joseph Conrad's "Heart of Darkness," the statement "We live as we dream - alone" reflects the isolation that individuals often experience in their lives. It suggests that while dreams can give a sense of purpose or vision, they ultimately exist within the individual's mind. This solitude can intensify feelings of disconnect from others and the world around us.

The second part of the quote, "While the dream disappears, the life continues painfully," indicates that as dreams fade away, the harsh realities of life persist. This ongoing struggle emphasizes the contrast between the idealism of dreams and the often harsh truths of existence, suggesting that life can be a painful journey once our dreams are no longer attainable.