In Act 4, Scene ii, of "Macbeth", discuss two examples of Macduff's son's wisdom.
First, the boy is smart enough to recognize that his mother is exaggerating and play along in a joke with her. When his mother says his father is dead and asks how he will get along, the boy teases that the will do what birds do, and take what he can get. He trips his mother up, and then announces that he realizes she is lying about his father's death:
Sirrah, your father's dead;
And what will you do now? How will you live?
As birds do, mother.
What, with worms and flies?
With what I get, I mean; and so do they.
Poor bird! thou'ldst never fear the net nor lime,
The pitfall nor the gin.
Why should I, mother? Poor birds they are not set for.
My father is not dead, for all your saying.
Next, he discusses with his mother what the definition of a traitor is, and suggests that perhaps traitors are fools - he shows that he recognizes already that traitors are most common than honest men, but suggesting that they can overpower the honest men:
Then the liars and swearers are fools,
for there are liars and swearers enow to beat
the honest men and hang up them.