3. No one should contract a fictitious engagement bearing on matters non-existing, or such as have only an imaginary or illegal cause. _Interpretation of contracts._--Jurists give the following rules regarding the interpretation of obscure clauses in contracts. The rules which are to guide the judge in regard to the law are the same as those which are to enlighten the consciences of the interested parties: "1. One should, in agreements, find out the mutual intention of the contracting parties, rather than stop at the literal sense of the words." (Art. 1156.) "2. When a clause is susceptible of a double meaning, one should understand it in the sense in which it may have some effect, rather than in the one in which it would not have any." (Art. 1157.) "4. That which is ambiguous is to be interpreted by what is customary in the country where the contract is made." (Art. 1159.) "5. One should supply in a contract its customary clauses, though they be not therein expressed." (Art. 1160.) "6. All the clauses of agreements are to be interpreted by one another, giving each the sense which results from the entire document." (Art. 1161.) "7. If doubtful, the agreement is to be interpreted against the stipulator, and in favor of him who contracted the obligation." (Art. 1162.) CHAPTER V. DUTIES TOWARDS THE LIBERTY AND TOWARDS THE HONOR OF OTHERS.--JUSTICE, DISTRIBUTIVE AND REMUNERATIVE; EQUITY. SUMMARY. =Liberty in general.=--Natural rights. =Slavery.=--Arguments of J. J. Rousseau against slavery, servitude; oppression of work under divers forms. =The honor of others.=--_Backbiting_ and _slander_. =Rash judgments.=--Analysis of a treatise of Nicole.--_Envy_; _rancor_; _delation_. =Justice, distributive and remunerative.=--To each according to his merits and his works. Equity. After self-preservation, the most sacred prerogative of man is _liberty_--that is to say, the right of using his faculties, both physical and moral, without injury to others, at his own risks and perils, and on his own responsibility. =51. Liberty--Natural rights.=--The word liberty sums up all that is understood by the _natural rights of man_, namely, the right to go and come, or _individual liberty_; the right to use his physical faculties to supply his wants, or _liberty of work_; the right to exercise his intelligence and reason, or _liberty of thought_; the right to honor God according to his lights, or _liberty of conscience_; the right to have a family, a wife and children, or the _family right_, and finally the right to keep what he has acquired, or the right of property.