Blackstone on Legal Interpretation

William Blackstone, from his Commentaries on the Laws of England:

“The fairest and most rational way to interpret the will of the legislator, is by exploring his intentions at the time when the law was made, by signs the most natural and probable.  And these signs are either the words, the context, the subject matter, the effects and consequence, or the spirit and reason of the law.  Let us take a short view of them all.”

“1. Words are generally to be understood in their usual and most known signification; not so much regarding the propriety of grammar, as their general and popular use. … Again; terms of art, or technical terms, must be taken according to the acceptation of the learned in each art, trade, and science. … Lastly, where words are clearly repugnant in two laws, the latter law takes the place of the elder: leges posteriores priores contrarias abrogant is a maxim of universal law, as well as of our own constitutions. And accordingly it was laid down by a law of the twelve tables at Rome, quod populus postremum jussit, id jus ratum esto.”

“2. If words happen to be still dubious, we may establish their meaning from the context; with which it may be of singular use to compare a word, or a sentence, whenever they are ambiguous, equivocal, or intricate.”

“3. As to the subject matter, words are always to be understood as having a regard thereto; for that is always supposed to be in the eye of the legislator, and all his expressions directed to that end.”

“4. As to the effects and consequence, the rule is, where words bear either none, or a very absurd signification, if literally understood, we must a little deviate from the received sense of them.”

“5. But, lastly, the most universal and effectual way of discovering the true meaning of a law, when the words are dubious, is by considering the reason and spirit of it; or the cause which moved the legislator to enact it.”