Question

Which parts of this excerpt from Christopher Marlowe’s The Tragical History of Doctor Faustus bring out the theme of forbidden knowledge?
CHORUS: Cut is the branch that might have grown full straight,
And burned is Apollo's laurel bough,
That sometime grew within this learned man.
Faustus is gone; regard his hellish fall,
Whose fiendful fortune may exhort the wise
Only to wonder at unlawful things,
Whose deepness doth entice such
forward wits To practise more than heavenly power permits