Supreme Court Justice Oliver Wendell Holmes was traveling by train to Washington, D.C., one morning nearly a century ago when a conductor asked for his ticket. Holmes looked in vain until the conductor reassured him, “Don’t worry about your ticket, Mr. Holmes. We all know who you are. When you get to your destination, you can find it and just mail it to us.—

“My dear man, the problem is not my ticket,— quipped Holmes, who was renowned for his quick wit. “The problem is … where am I going?—

We face a similar guessing game as a nation every time a new Supreme Court justice is chosen.

It is a question that has plagued presidents and Senators since the creation of the Republic. In selecting a new member of the Supreme Court, it is never clear where a new justice will go politically or jurisprudentially or historically. It is a question that many are asking anew with the confirmation proceedings of Judge Sonia Sotomayor, who remains an “unknown— in both her philosophy and potential on the court.

All presidents want to add a “great one— to their legacy, but few have achieved that goal. Indeed, many justices selected with virtual American Kennel Club papers of breeding and education have proven virtual judicial duds with little vision or influence on the law. Conversely, some of our greatest justices did not graduate from law school or sit on a single court before joining the high court.

While the selection of the greatest justices tends to have a considerable degree of subjectivity, many of the most commonly cited justices like Joseph Story, Stephen Field, Louis Brandeis, Hugo Lafayette Black, William Douglas, Earl Warren and others suggest that there is no “profile— for the selection of great justices. They also suggest that the most common criteria are poor predicative measures.

The most obvious is prior judicial experience. Presidents routinely select justices from a small number of law schools (particularly Harvard and Yale) and from the federal court of appeals. Yet, some of the greatest justices came to the court without prior judicial experience or elite law school backgrounds.

Former Chief Justice Stephen Field is a particularly good example of the unpredictability of greatness. Field briefly studied law in New York before getting the gold rush bug in 1849 and heading west. He became a frontier prospector and lawyer. He was involved in armed fights and at least one duel. He was disbarred after a fight with a judge. (The chief justice of the California Supreme Court, David Terry, had a long feud with Field. In 1889, Terry assaulted Field in a restaurant and was shot and killed by the marshal guarding Field. While the marshal was indicted, he was later cleared by, you guessed it, the United States Supreme Court). Field would become one of the most brilliant and influential justices in history.

Brilliance is actually a liability in modern nominations. Presidents and Senators tend to look for “safe— nominees, preferably with little writing or creative thinking in their past. Indeed, some justices were nominated largely because their portfolios were all but empty, like Sandra Day O’Connor, Clarence Thomas and David Souter. O’Connor’s file appeared composed of little more than a birth certificate and a bar license. Souter was found all but living as a hermit in the woods of New Hampshire with solid but conventional opinions on the New Hampshire Supreme Court and federal court of appeals. Thomas not only had not written any substantive articles, but he told the Senate Judiciary Committee that he had given little thought to Roe v. Wade and its constitutional basis. Perfect.

Conversely, the most influential judges are routinely bypassed. For example, legal historians will always marvel at the fact that conservative Judge Richard Posner of the United States Court of Appeals for the 7th Circuit in Chicago was never placed on the court. Posner is one of the fathers of the law and economics movement and one of the most influential legal minds in the history of American law. His influence and intelligence dwarfs the conservative nominees appointed during his lifetime. On the left, Sotomayor sits with an equally influential liberal Judge Guido Calabresi who is widely accepted as one of the most brilliant minds of his generation.

Nominees are selected by politicians often for their optics rather their opinions. This nomination was viewed as a rare opportunity to appoint a Brandeis or a Brennan — a nominee who could bring demonstrated intellectual depth to the development of jurisprudence. Obama had the votes to select such a person but still chose a nominee with a compelling personal story but a largely unremarkable body of work as a jurist. For many academics, it reaffirmed the view that the only chance for a truly “great— theoretician on the court is a purely accidental selection of a stealth genius.

Sotomayor is a relative rare commodity in that, unlike many past nominees with few written opinions, she has hundreds of opinions over the course of 18 years. Review of these opinions by academics and newspapers describe Sotomayor’s opinions as extremely narrow and conventional. There is no single opinion that stands out as particularly profound or clearly establishes why Sotomayor should be elevated to the court — though this does not distinguish her from other recent nominees like Samuel Alito.

Senators often quote legal geniuses like Brandeis. However, they rarely like the same characteristics in living nominees. The best way to the court is to avoid creative thoughts or writings. Chief Justice John Roberts is an example of how one can maximize one’s chances for the court by minimizing any provocative thoughts or utterances. Yet, the great advances in law were the product of people who could transcend establishment or conventional thinking — often displaying this ability before they were selected for the court. Justices with formulaic careers are more likely to result in formulaic opinions.

While Senators often portray the members of the court as the greatest legal minds, the reality is far different. When it comes to trout and justices, Senators prefer to fish in the shallow end of the pond. History has shown that brilliance is hard to hide on the Supreme Court, but much harder to recognize in our modern confirmation process.

Jonathan Turley is the Shapiro professor of public interest law at George Washington Law School, where he teaches a course on the Constitution and the Supreme Court.