[expression] 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 is subjective or lacks clearly defined parameters. 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:
I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description ["hard-core pornography"], and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that.
Adapted from Wikipedia
When I design online ads for American Apparel, I almost always look for an angle that will provoke. Outrage, self-righteousness, and titillation all work equally well. Naturally, the sexy ones are probably those you remember most, but the formula worked for all types of images. Photos of kids dressed up like adults, dogs wearing clothes, ad copy that didn’t make any sense—all high-valence, viral images. If I could generate a reaction, I could propel the ad from being something I had to pay for people to see (by buying ad inventory) to something people would gladly post on the front page of their highly trafficked websites.
This cult of "intelligence" centers on the idea that human cleverness is the supreme value . . . [but] all around us, we can see people trying to solve by logical argument or by the acquiring of information, problems that can only be dealt with by a change of heart—a change of attitude and new policy and direction. But this is the last thing we try . . . in contemporary culture, the passionate, quasi-religious exaltation of our pure cognitive faculties is surely a defense mechanism against this awkward fact.
Some new products and ideas slip into the well-worn grooves of people's expectations. In fifteen out of the last sixteen ...