Question

Antonio seems to have it all. Why is antonio so sad?Why does not he know the cause of his sadness?

Answer 1

Antonio, a merchant, is in a melancholic state of mind and unable to find a reason for his depression. Solanio suspects Antonio is worried about his ships at sea with all their cargo but Antonio denies this reason. This unexplained melancholy is common in Shakespeare's plays. Still one could speculate that Antonio is self-absorbed. I always thought he is merely lonely. Helping Bassanio with his gamble (wooing Portia) seems to help.