There is no paradox. Ideas have power, and ideas are spread through speech. However, speech does not provide the ground in which ideas grow - environment and society does that. Prohibiting speech cannot prevent the manifestation of ideas, and cannot even really prevent their spread, but is instead an indicator of broader conditions being unfavorable to those ideas. Popular ideas cannot be effectively repressed, only unpopular ones.
Really? In the Soviet Union, prohibited ideas still spread. In China and modern Russia, dissidents still exist. The spread of ideas cannot be stopped unless people don't want to hear them in the first place.
