How does Juliet's father change between Act I, Scene 2 and Act III, Scene 5 of Shakespeare's Romeo and Juliet?

Lord Capulet totally changes his mind about the marriage of his daughter Juliet and Count Paris between Acts I and III. In Act I, Scene 2, while not completely against such a marriage, Capulet suggests that Juliet, who is only thirteen, is simply too young and that Paris should wait at least two years. The Count, however, is quite persuasive and notes that other girls Juliet's age are already married and pregnant. At this, Capulet...

Lord Capulet totally changes his mind about the marriage of his daughter Juliet and Count Paris between Acts I and III. In Act I, Scene 2, while not completely against such a marriage, Capulet suggests that Juliet, who is only thirteen, is simply too young and that Paris should wait at least two years. The Count, however, is quite persuasive and notes that other girls Juliet's age are already married and pregnant. At this, Capulet seems to relent a little and urges Paris to court Juliet and win her over. He informs Paris that Juliet will have to be in love in order for him to agree to the marriage:

But woo her, gentle Paris, get her heart;
My will to her consent is but a part.
And, she agreed, within her scope of choice
Lies my consent and fair according voice.

In this scene, Capulet reveals himself to be a loving and wise father. Since Juliet is his only living child, he is naturally protective of her and seems to be looking out for her happiness.

In Act III, Scene 4, Capulet abruptly changes his mind and agrees to the marriage between Paris and Juliet. Saying that the family needs to get over the death of Tybalt, he believes the marriage will help them overcome their grief. Of course, Capulet knows nothing about Juliet's marriage to Romeo. In Scene 5, he informs the distraught Juliet of his plans. The girl immediately refuses, causing Capulet to launch into an enraged rant where he threatens to throw Juliet out on the street and disown her.

Capulet's change of mind, and his quick temper, seem somewhat out of line with Shakespeare's earlier characterization. Paris has done none of the things which Capulet had earlier requested, so by agreeing to the marriage, Capulet has done a complete about-face. Of course, the marriage plan is essential to Shakespeare's plot and is one more complication which will lead to the tragic ending of the play.