5. _Duties towards the liberty of others._--These are rather the duties of the State than of the individual. They consist in respecting in others the liberty of conscience, the liberty of labor, individual liberty, personal responsibility, all of which are the _natural rights_ of man. However, private individuals may themselves also fail in this kind of duties. The violation of the liberty of conscience is called _intolerance_; it consists either in employing force to constrain the consciences, or in imputing bad morals or bad motives to those who do not think as we do. The virtue opposed to intolerance is _tolerance_, a disposition of the soul which consists, not in approving what we think false, but in respecting in others what we wish they should respect in us, namely, conscience. One may also violate individual liberty, the liberty of labor, in keeping one's fellow-beings in _slavery_; but slavery is rather a social institution than an individual act. However, there may be cases where one may seek to injure other people's work, in restraining others by threats from work; which, for example, takes sometimes place in workmen's strikes. There is also a certain way of domineering over the freedom of others without restraining it materially, which constitutes real _tyranny_; it is the dominion which a strong will exercises over a feeble will, and of which it too often is tempted to take advantage. On the contrary, it is a duty, not only to respect the liberty of others, but also to encourage it, to develop it, to enlighten it through education. 6. _Duties relating to friendship._--All the preceding duties are the same towards all men. There are others which concern more particularly certain men, those, for example, to whom we are attached either by congeniality of disposition or uniformity of occupation, or a common education, etc., those, namely, whom we call _friends_. The duties relating to friendship are: 1, to choose well one's friends; to choose the honest, and enlightened, in order to find in their society encouragement to right-doing. Nothing more dangerous than pleasure-friends or interested friends, united by vices and passions, instead of being united by wisdom and virtue; 2, the friends once chosen, the reciprocal duty is _fidelity_. They should treat each other with perfect _equality_ and with _confidence_. They owe each other _secrecy_ when they mutually entrust their dearest interests; they owe each other _self-devotion_ when they need each other's help. Finally, they owe to each other in a more strict and rigorous a sense, all they generally owe to other men, for the faults or crimes against humanity in general assume a still more odious character when against friends.