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. 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" majority opinion in the 1919 case of Schenck v. United States, and is one of the most influential American common law judges. Holmes retired from the Court at the age of 90, making him the oldest Justice in the Supreme Court's history. He also served as an Associate Justice and as Chief Justice on the Massachusetts Supreme Judicial Court, and was Weld Professor of Law at the Harvard Law School, of which he was an alumnus.

Profoundly influenced by his experience fighting in the American Civil War, Holmes helped move American legal thinking away from formalism and towards legal realism, as summed up in his maxim: "The life of the law has not been logic; it has been experience." Holmes espoused a form of moral skepticism and opposed the doctrine of natural law, marking a significant shift in American jurisprudence. As he wrote in one of his most famous decisions, his dissent in Abrams v. United States (1919), he regarded the United States Constitution as "an experiment, as all life is an experiment" and believed that as a consequence "we should be eternally vigilant against attempts to check the expression of opinions that we loathe and believe to be fraught with death." During his tenure on the Supreme Court, to which he was appointed by President Theodore Roosevelt, he supported efforts for economic regulation and advocated broad freedom of speech under the First Amendment. These positions as well as his distinctive personality and writing style made him a popular figure, especially with American progressives, despite his deep cynicism and disagreement with their politics. His jurisprudence influenced much subsequent American legal thinking, including judicial consensus supporting New Dealregulatory law, pragmatism, critical legal studies, and law and economics. The Journal of Legal Studies has identified Holmes as one of the three most cited American legal scholars of the 20th century.

Holmes was born in Boston, Massachusetts, the son of the prominent writer and physician Oliver Wendell Holmes, Sr. and abolitionist Amelia Lee Jackson. As a young man, Holmes loved literature and supported the abolitionist movement that thrived in Boston society during the 1850s. He graduated from Harvard University in 1861, where he was elected to the Phi Beta Kappa honor society and was a brother of the Alpha Delta Phi. Additionally, Holmes was a member of the Porcellian Club, an exclusive organization, during his senior year at Harvard.

Whenever he could, Holmes visited London during the social season of spring and summer. He formed his closest friendships with men and women there, and became one of the founders of what was soon called the "sociological" school of jurisprudence in Great Britain, which would be followed a generation later by the "legal realist" school in America.

Holmes practiced admiralty law and commercial law in Boston for fifteen years. In 1870, Holmes became an editor of the American Law Review, edited a new edition of Kent's Commentaries on American Law in 1873, and published numerous articles on the common law. In 1881, he published the first edition of his well regarded book The Common Law, in which he summarized the views developed in the preceding years. In the book, Holmes sets forth his view that the only source of law, properly speaking, is a judicial decision. Judges decide cases on the facts, and then write opinions afterward presenting a rationale for their decision. The true basis of the decision is often an "inarticulate major premise" outside the law. A judge is obliged to choose between contending legal theories, and the true basis of his decision is necessarily drawn from outside the law. These views endeared Holmes to the later advocates of legal realism and made him one of the early founders of law and economics jurisprudence.

Holmes was considered for a federal court judgeship in 1878 by President Rutherford B. Hayes, but Massachusetts Senator George Frisbie Hoar convinced Hayes to nominate another candidate. In the fall of 1882, Holmes became a professor at Harvard Law School. On Friday 8 December 1882, Supreme Judicial Court of Massachusetts associate justice Otis Lord decided to resign, giving outgoing Republican governor John Davis Long a chance to appoint his successor, if it could be done before the Massachusetts Governor's Council adjourned at 3pm. Holmes quickly agreed, and there being no objection by the Council, took the oath of office on 15 December 1882. His resignation was accepted effective that day by the law school. On 2 August 1899, Holmes became Chief Justice of the Massachusetts Supreme Judicial Court following the death of Walbridge A. Field.

During his service on the Massachusetts court, Holmes continued to develop and apply his views of the common law, usually following precedent faithfully. He issued few constitutional opinions in these years, but carefully developed the principles of free expression as a common law doctrine. He departed from precedent to recognize workers' right to organize trade unions as long as no violence or coercion was involved, stating in his opinions that fundamental fairness required that workers be allowed to combine to compete on an equal footing with employers.

On August 11, 1902, Holmes received a recess appointment from President Theodore Roosevelt naming Holmes to a seat on the United States Supreme Court vacated by Justice Horace Gray, who had retired in July 1902 as a result of illness. The appointment was made on the recommendation of Senator Henry Cabot Lodge (Roosevelt reportedly admired Holmes's "Soldier's Faith" speech as well). Holmes' appointment has been referred to as one of the few Supreme Court appointments in history not motivated by partisanship or politics, but strictly based on the nominee's contribution to law.

Formally nominated on December 2, 1902, Holmes was unanimously confirmed by the United States Senate on December 4, receiving his commission the same day. According to some accounts, Holmes assured Roosevelt that he would vote to sustain the administration's position that not all the provisions of the United States Constitution applied to possessions acquired from Spain, an important question on which the Court was then evenly divided. On the bench, Holmes did vote to support the administration's position in the "Insular Cases." However, he later disappointed Roosevelt by dissenting in Northern Securities Co. v. United States, a major antitrust prosecution; the majority of the court, however, did rule against Holmes and sided with Theodore Roosevelt's belief that Northern Securities violated the Sherman Anti - Trust Act. This action by Holmes brought his relationship with Theodore Roosevelt to an abrupt halt.

Holmes was known for his pithy, short, and frequently quoted opinions. In more than thirty years on the Supreme Court bench, he ruled on cases spanning the whole range of federal law. He is remembered for prescient opinions on topics as widely separated as copyright, the law of contempt, the antitrust status of professional baseball, and the oath required for citizenship. Holmes, like most of his contemporaries, viewed the Bill of Rights as codifying privileges obtained over the centuries in English and American law. Beginning with his first opinion for the Court, in Otis v. Parker, Holmes declared that "due process of law," the fundamental principle of fairness, protected people from unreasonable legislation, but was limited to only those fundamental principles enshrined in the common law and did not protect most economic interests. In a series of opinions surrounding the WWI Espionage Act and Sedition Act, he held that the freedom of expression guaranteed by federal and state constitutions simply declared a common - law privilege to do harm, except in cases where the expression, in the circumstances in which it was uttered, posed a "clear and present danger" of causing some harm that the legislature had properly forbidden. In Schenck v. United States, Holmes announced this doctrine for a unanimous Court, famously declaring that the First Amendment would not protect a person "falsely shouting fire in a theatre and causing a panic."

The following year, however, in Abrams v. United States, Holmes — influenced by Zechariah Chafee's article "Freedom of Speech in War Time" — delivered a strongly worded dissent in which he criticized the majority's use of the clear and present danger test, arguing that protests by political dissidents posed no actual risk of interfering with war effort. In his dissent, he accused the Court of punishing the defendants for their opinions rather than their acts. Although Holmes evidently believed that he was adhering to his own precedent, many later commentators accused Holmes of inconsistency, even of seeking to carry favor with his young admirers. The Supreme Court departed from his views where the validity of a statute was in question, adopting the principle that a legislature could properly declare that some forms of speech posed a clear and present danger, regardless of the circumstances in which they were uttered.

From Taft's departure on February 3, 1930 until Hughes took office on February 24, 1930, Holmes was briefly Acting Chief Justice under 36 Stat. 1152.

By the time Holmes was 80, he had dissented in so many opinions that he became known as "The Great Dissenter," a title which has been carried through the years to refer to various U.S. Supreme Court justices, including Justice John Marshall Harlan, with the latest being Justice William Brennan.

In 1927, Holmes wrote the majority opinion in the Buck v. Bell case that upheld the forced sterilization of a woman who was claimed to be of below average intelligence. In support of his argument that the interest of the states in a "pure" gene pool outweighed the interest of individuals in their bodily integrity, he argued:

Holmes concluded his argument by declaring that "Three generations of imbeciles are enough".

Justice Holmes laid the foundation of healthy and constructive scepticism in the law. Hughes writes: "Though another half century was to elapse before the appearance of Ogden and Richard's The Meaning of Meaning, exploration of meaning of meaning of law was Holmes's pioneer enterprise." Hughes further writes: "To me, Mr. Justice Holmes is a prophet of the Law."

In 1881, Holmes published The Common Law, representing a new departure in legal philosophy. By his writings, he changed attitude to law. An excerpt from the opening passage captures the pragmatic theme of that work and of Holmes's philosophy of law: 'The life of the law has not been logic; it has been experience.'

In a dissenting opinion in Lochner v. New York (1905) Holmes declared that the law should develop along with society and that the 14th Amendment did not deny states a right to experiment with social legislation. He also argued for judicial restraint, asserting that the Court should not interpret the Constitution according to its own social philosophy. Francis Biddle writes: "He was convinced that one who administers constitutional law should multiply his skepticisms to avoid heading into vague words like 'liberty', and reading into law his private convictions or the prejudices of his class." Biddle also tells us that Holmes "refused to let his preferences (other men were apt to call them convictions) interfere with his judicial decisions…… The steadily held determination to keep his own views isolated from his professional work is aptly shown by his famous remark in the Lochner case - the Fourteenth Amendment does not enact Mr. Herbert Spencer's Social Statics.... A constitution is not intended to embody a particular economic theory."

According to Holmes, 'men make their own laws;... these laws do not flow from some mysterious omnipresence in the sky, and ... judges are not independent mouthpieces of the infinite., 'The common law is not a brooding omnipresence in the sky. Holmes compared the Law to a bad man "who cares only for the material consequences of things" rather than as an independent moral entity. Holmes defined the law in accordance with his pragmatic judicial philosophy. Rather than a set of abstract, rational, mathematical, or in any way unwordly set of principals, Holmes said that '[t]he prophecies of what the courts will do in fact, and nothing more pretentious, are what I mean by the law. Accordingly, Holmes thought that only a judge or lawyer who is acquainted with the historical, social, and economic aspects of the law will be in a position to fulfill his functions properly.

As a justice of US Supreme Court, Holmes introduced a new method of constitutional interpretation. He challenged the traditional concept of constitution. Holmes also protested against the method of abstract logical deduction from general rules in the judicial process. According to Holmes, lawyers and judges are not logicians and mathematicians. The books of the laws are not books of logic and mathematics. He writes: "The life of the law has not been logic; it has been experience. The felt necessities of the time, the prevalent moral and political theories, intuitions of public policy, avowed or unconscious, and even the prejudices which judges share with their fellow men, have had a good deal more to do than syllogism in determining the rules by which men should be governed. The law embodies the story of a nation's development through many centuries, and it cannot be dealt with as if it contained only the axioms and corollaries of a book of mathematics.

In Lochner v. New York (1905) he observes that, 'General proposition do not decide concrete cases.

Holmes, also insisted on the separation of 'ought' and 'is' which are obstacles in understanding the realities of the law. As a moral sceptic, Holmes tells us that if you want to know the real law, and nothing else, you must consider it from the point of view of 'bad man' who cares only from material consequences of the courts' decisions, and not from the point of view of good man, who find his reasons for conduct "in the vaguer sanctions of his conscience. The law is full of phraseology drawn from morals, and talks about rights and duties, malice, intent, and negligence - and nothing is easier in legal reasoning than to take these words in their moral sense. Holmes said: "I think our morally tinted words have caused a great deal of confused thinking." But Holmes is not unconcerned with moral question. He writes: "The law is the witness and external deposit of our moral life. Its history is the history of the moral development of the race. The practice of it, in spite of popular jests, tends to make good citizens and good men. When I emphasize the difference between law and morals I do so with reference to a single end, that of learning and understanding the law. George Washington University law professor Jeffrey Rosen summarized Holmes' views on politics and the law this way: "Holmes was a cold and brutally cynical man who had contempt for the masses and for the progressive laws he voted to uphold."

Holmes served on the court until January 12, 1932, when his brethren on the court, citing his advanced age, suggested that the time had come for him to step down. By that time, at 90 years of age, he was the oldest justice to serve in the court's history. Three years later, Holmes died of pneumonia in Washington, D.C. in 1935, two days short of his 94th birthday. In his will, Holmes left his residuary estate to the United States government (he had earlier said that "Taxes are what we pay for civilized society" in Compañia General De Tabacos De Filipinas vs. Collector of Internal Revenue, 275 U.S. 87, 100 (1927).) After his death, his personal effects included his Civil War Officer's uniform still stained with his blood and 'torn with shot' as well as the carefully wrapped Minié balls that had wounded him three times in separate battles. He was buried in Arlington National Cemetery. The United States Postal Service honored Holmes with a Prominent Americans series (1965 – 1978) 15¢ postage stamp.

Holmes's papers, donated to Harvard Law School, were kept closed for many years after his death, a circumstance that gave rise to numerous speculative and fictionalized accounts of his life. Catherine Drinker Bowen's fictionalized biography "Yankee from Olympus" was a long time bestseller, and the 1951 Hollywood motion picture The Magnificent Yankee was based on a highly fictionalized play about Holmes's life. Since the opening of the extensive Holmes papers in the 1980s, however, there has been a series of more accurate biographies and scholarly monographs.

Harvard Medical School names one of its five student societies after his father, Doctor Oliver Wendell Holmes.

American actor Louis Calhern portrayed Holmes in the 1946 play The Magnificent Yankee, with Dorothy Gish as Holmes's wife, and in 1950, Calhern repeated his performance in MGM's film version, for which he received his only Academy Award nomination. Ann Harding co-starred in the film. A 1965 television adaptation of the play starred Alfred Lunt and Lynn Fontanne in one of their few appearances on the small screen.

Holmes is featured in the following passage by Isaac Asimov:

Holmes, in his last years, was walking down Pennsylvania Avenue with a friend, when a pretty girl passed. Holmes turned to look after her. Having done so, he sighed and said to his friend, "Ah, George, what wouldn't I give to be seventy - five again?"

His quote is shown on the wall in the school in the Gus Van Sant film Elephant.

In the movie Judgment at Nuremberg (1961), defense advocate Hans Rolfe quotes Justice Oliver Wendell Holmes twice with the following:

This responsibility will not be found only in documents that no one contests or denies. It will be found in considerations of a political or social nature. It will be found, most of all in the character of men.

Holmes appears as the principle character in the Bangsian Fantasy story "With Enemies Like These" in the volume Lawyers in hell, part of the Heroes in Hell shared universe series.