By the time of his essay The Path of the Law, Holmes had completed the evolution to a behaviorist theory of law. Whatever you may think of Holmes's jurisprudence, The Path of the Law is an unambiguously great exercise in legal philosophy; certainly it withstands the test of time much better than The Common Law. Laws should be written, we learn, from the standpoint of "the bad man," he who will do the absolute minimum necessary to avoid the sanctions of his neighbors. In other words, it must create objective standards, that do not depend on the personal virtue or goodwill of the citizens. When the law seeks to determine the "intent" of someone who committed an act for which he is on trial, it is not seeking to determine whether he meant to do good or harm. The law seeks to know only whether he knew what the results of his action would be. The inquiry can be made only by considering the defendant's observable behavior.

The Path of the Law by Oliver Wendell Holmes, Jr. was originally published in the "Harvard Law Review" in 1897.

Oliver Wendell Holmes, Jr. (March 8, 1841–March 6, 1935) was an American jurist who served as an Associate Justice of the Supreme Court of the United States from 1902 to 1932, and as Acting Chief Justice of the United States January–February 1930. Noted for his long service, his concise and pithy opinions and his deference to the decisions of elected legislatures, he is one of the most widely cited United States Supreme Court justices in history, particularly for his "clear and present danger" opinion for a unanimous Court in the 1919 case of Schenck v. United States, and is one of the most influential American common law judges, honored during his lifetime in Great Britain as well as the United States. Holmes retired from the Court at the age of 90 years, 309 days, making him the oldest Justice in the Supreme Court's history.