A Clockwork Orange challenges the ideas of free will and power in society.  On the one hand, Alex and his friends choose freely to exert their will upon others.  They are incredibly violent towards other boys and women, and they spend much time abusing each other and themselves.  When Alex is finally arrested, the government decides to "cure" him through a psychologically invasive method.  The government feels that they have the right to do this in order to protect others in society who are being hurt by Alex.  However, Alex is stripped of his personality, and when he is "cured," it is clear that the method has only worked to scare Alex into his more appropriate behavior.  In the end, Alex resorts to his old ways.  So the novel presents the tension between free will and power and questions the rights that people assume they have when imposing their will on others.