Shakespeare defends that humans are doomed to an inevitable fate through the plot line and characters of the play Romeo and Juliet. Argument 1: Romeo and Juliet met by fate
It is not merely a coincidence that Romeo and Juliet meet in the first place. A serving man comes across Romeo and Benvolio in the first act, unaware that they are Montagues, and informs them about the Capulet party: "My master is the great rich Capulet, and, if you be not / of the house of Montagues, I pray come and crush a / cup of wine" (I ii, 86-88). It is by fate that Romeo and Benvolio run into the Capulet serving man and discover the party. It is not just a simple accident that the serving man tells the two cousins about the party at which Romeo is destined, yet unaware, that he will meet his love. Furthermore, before Romeo attends the Capulet party, he says, "Some consequence yet hanging in the stars / shall bitterly begin this fearful date" (I iv, 114-115). Romeo already predicts what the fates have in store as he says something bad might transpire if he dares to show up at the party, where he will meet Juliet. It is fate that they meet because Romeo says it himself. The final deaths of them both (Romeo and Juliet) is the "consequence" that he is talking about and the bitterness that starts the pathway to their ultimate tragedy is their first encounter, since they are supposed to be opposing enemies. For these reasons, Romeo and Juliet's first meeting is compulsory and sure to happen, fate being the most powerful force at work, determining their tragic future.
Argument 2: Star-cross'd lovers
Though they are the offspring of two families who have held a grudge over each other since antiquity, Romeo and Juliet are doomed to be in love. When Romeo discovers who Juliet is, he says to himself, "O dear account! My life is my foe's debt" (I v, 132). Despite the fact that they were born into feuding families, Romeo can't help but love Juliet because he already loves her...