“Thought is no longer theoretical. As soon as it functions it offends or reconciles, attracts or repels, breaks, dissociates, unites or reunites; it cannot help but liberate or enslave. Even before prescribing, suggesting a future, saying what must be done, even before exhorting or merely sounding an alarm, thought, at the level of its existence, in its very dawning, is in itself an action-a perilous act.”