Question

ROMEO
Peace, peace, Mercutio, peace!
Thou talk'st of nothing.
MERCUTIO
True, I talk of dreams,
Which are the children of an idle brain,
Begot of nothing but vain fantasy,
Which is as thin of substance as the air
And more inconstant than the wind
What kind of dreams is Mercutio describing, especially when he calls them "children of an idle brain"?
1. childish, immature thoughts
2. the strange thoughts that come when our minds are at rest
3. the dreams and hopes of our youth that have long since blown away
4. the nightmares that come from an overactive imagination