Page:William Blackstone, Commentaries on the Laws of England (3rd ed, 1768, vol I).djvu/85

But here a very natural, and very material, queſtion ariſes: how are theſe cuſtoms or maxims to be known, and by whom is their validity to be determined? The anſwer is, by the judges in the ſeveral courts of juſtice. They are the depoſitary of the laws; the living oracles, who muſt decide in all caſes of doubt, and who are bound by an oath to decide according to the law of the land. Their knowlege of that law is derived from experience and ſtudy; from the “viginti annorum lucubrationes,” which Forteſcue^[1] mentions; and from being long perſonally accuſtomed to the judicial deciſions of their predeceſſors. And indeed theſe judicial deciſions are the principal and moſt authoritative evidence, that can be given, of the exiſtence of ſuch a cuſtom as ſhall form a part of the common law. The judgment itſelf, and all the proceedings previous thereto, are carefully regiſtered and preſerved, under the name of records, in public repoſitories ſet apart for that particular purpoſe; and to them frequent recourſe is had, when any critical queſtion ariſes, in the determination of which former precedents may give light or aſſiſtance. And therefore, even ſo early as the conqueſt, we find the “praeteritorum memoria eventorum” reckoned up as one of the chief qualifications of thoſe who were held to be “legibus patriae optime inſtituti^[2].” For it is an eſtabliſhed rule to abide by former precedents, where the ſame points come again in litigation; as well to keep the ſcale of juſtice even and ſteady, and not liable to waver with every new judge’s opinion; as alſo becauſe the law in that caſe being ſolemnly declared and determined, what before was uncertain, and perhaps indifferent, is now become a permanent rule, which it is not in the breaſt of any ſubſequent judge to alter or vary from, according to his private ſentiments: he being ſworn to determine, not according to his own private judgment, but according to the known laws and cuſtoms of the land; not delegated to pronounce a new law, but to maintain and expound the old one. Yet this rule admits of exception, where the former determination is moſt evidently contrary to reaſon;

1. cap. 8.
2. Seld. review of Tith. c. 8.

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