 There are three main arguments that can be used to defend a principle of freedom of conscience. Two of them are frequently found in the 16th and 17th Century philosophical literature: they are the “argument from ineffectiveness or hypocrisy” and the “argument from ignorance” (Sorabji 2014: 139). A third argument, which might be called “argument from legitimization”, was put forward by John Stuart Mill. Let us examine them in order.