All laws, written, and unwritten, have need of interpretation. The unwritten law of nature, though it be easy to such, as without partiality and passion, make use of their natural reason, and therefore leaves the violators thereof without excuse; yet considering there be very few, perhaps none, that in some cases are not blinded by self-love, or some other passion; it is now become of all laws the most obscure, and has consequently the greatest need of able interpreters. The written laws, if they be short, are easily misinterpreted, from the divers significations of a word, or two: if long, they be more obscure by the divers significations of many words: insomuch as no written law, delivered in few, or many words, can be well understood, without a perfect understanding of the final causes, for which the law was made; the knowledge of which final causes is in the legislator. To him therefore there cannot be any knot in the law, insoluble; either by finding out the ends, to undo it by; or else by making what ends he will, as Alexander did with his sword in the Gordian knot, by the legislative power; which no other interpreter can do. [Sidenote: The authentical interpretation of law is not that of writers.] The interpretation of the laws of nature, in a commonwealth, dependeth not on the books of moral philosophy. The authority of writers, without the authority of the commonwealth, maketh not their opinions law, be they never so true. That which I have written in this treatise, concerning the moral virtues, and of their necessity for the procuring, and maintaining peace, though it be evident truth, is not therefore presently law; but because in all commonwealths in the world, it is part of the civil law. For though it be naturally reasonable; yet it is by the sovereign power that it is law: otherwise, it were a great error, to call the laws of nature unwritten law; whereof we see so many volumes published, and in them so many contradictions of one another, and of themselves. [Sidenote: The interpreter of the law is the judge giving sentence viva voce in every particular case.] The interpretation of the law of nature, is the sentence of the judge constituted by the sovereign authority, to hear and determine such controversies, as depend thereon; and consisteth in the application of the law to the present case. For in the act of judicature, the judge doth no more but consider, whether the demand of the party, be consonant to natural reason, and equity; and the sentence he giveth, is therefore the interpretation of the law of nature; which interpretation is authentic; not because it is his private sentence; but because he giveth it by authority of the sovereign, whereby it becomes the sovereign’s sentence; which is law for that time, to the parties pleading. [Sidenote: The sentence of a judge does not bind him, or another judge to give like sentence in like cases ever after.]