  Liberty also requires that the laws concern only threats to public order and security, since such laws will protect us from harm while leaving us free to do as many other things as possible. Thus, for instance, the laws should not concern offenses against God, since He does not require their protection. They should not prohibit what they do not need to prohibit: "all punishment which is not derived from necessity is tyrannical. The law is not a mere act of power; things in their own nature indifferent are not within its province" (SL 19.14). The laws should be constructed to make it as easy as possible for citizens to protect themselves from punishment by not committing crimes. They should not be vague, since if they were, we might never be sure whether or not some particular action was a crime. Nor should they prohibit things we might do inadvertently, like bumping into a statue of the emperor, or involuntarily, like doubting the wisdom of one of his decrees; if such actions were crimes, no amount of effort to abide by the laws of our country would justify confidence that we would succeed, and therefore we could never feel safe from criminal prosecution. Finally, the laws should make it as easy as possible for an innocent person to prove his or her innocence. They should concern outward conduct, not (for instance) our thoughts and dreams, since while we can try to prove that we did not perform some action, we cannot prove that we never had some thought. The laws should not criminalize conduct that is inherently hard to prove, like witchcraft; and lawmakers should be cautious when dealing with crimes like sodomy, which are typically not carried out in the presence of several witnesses, lest they "open a very wide door to calumny" (SL 12.6).