I know it when I see it

The phrase "I know it when I see it" is a colloquial expression by which a speaker attempts to categorize an observable fact or event, although the category subjective or lacks clearly defined parameters. It has been a common expression since at least the 19th century. A similar phrase appears in A. Conan Doyle's "The Hound of the Baskervilles," in which Sherlock Holmes comments on the quality of a portrait by stating "I know what is good when I see it." The phrase was used in 1964 by United States Supreme Court Justice Potter Stewart to describe his threshold test for obscenity in Jacobellis v. Ohio. In explaining why the material at issue in the case was not obscene under the Roth test, and therefore was protected speech that could not be censored, Stewart wrote: The expression became one of the best-known phrases in the history of the Supreme Court. Though "I know it when I see it" is widely cited as Stewart's test for "obscenity", he did not use the word "obscenity" himself in his short concurrence, but stated that he knew what fitted the "shorthand description" of "hard-core pornography" when he saw it. Stewart's "I know it when I see it" standard was praised as "realistic and gallant" and an example of candor. It has also been critiqued as being potentially fallacious, due to individualistic arbitrariness. History The Supreme Court of the United States' rulings concerning obscenity in the public square have been unusually inconsistent. Though First Amendment free speech protections have always been taken into account, both Constitutional interpretationalists and originalists have limited this right to account for public sensibilities. Before Roth v. United States in 1957, common law rules stemming from the 1868 English case Regina v Hicklin have articulated that anything which "deprave[s] and corrupt[s] those whose minds are open to such immoral influences" was said to be obscene, and therefore banned. The Roth case gave a clearer standard for deciding what constitutes pornography, stating that obscenity is material where the "dominant theme taken as a whole appeals to the prurient interest", and that the "average person, applying contemporary community standards" would disapprove of, reaffirming the 1913 case United States v. Kennerley. This standard allowed for many works to be called obscene, and though the Roth decision acknowledged "all ideas having even the slightest redeeming social importance ...