Slippery slope

A "slippery slope" is, according to Merriam-Webster, is "a course of action that seems to lead inevitably from one action or result to another with unintended consequences." It is often used as a rhetorical device to suggest that a seemingly innocent small action will lead inevitably to a disastrous result.

As a fallacy

An argument of this form is invalid if there is no necessary logical connection between its premise and its conclusion. Indeed, it barely has any formal structure beyond if p, then q. Whilst it is therefore a logical fallacy, its emotive appeal remains a depressingly effective way of convincing those who don't know their modus ponens from their elbow. If the conclusion does follow from the premise, then the argument is not a fallacious slippery-slope argument, but instead a reductio ad absurdum, which is a valid argument.

Examples

• If we allow this increase in administrative fees, soon tuition will double!
• If we don't stop the terrorists in Iraq, they'll invade Maine next!
• If we send in 100,000 troops, the next thing you know we'll be in a quagmire like Vietnam!
• You are not aware of the caliber of disaster indicated by the presence of a pool table in your community.... I say that any boob can take and shove a ball in a pocket. And I call that sloth, the first big step on the road to the depths of degraday—I say, first, medicinal wine from a teaspoon, then beer from a bottle! An' the next thing ya know, your son is playin' for money in a pinch-back suit. And list'nin to some big out-a-town Jasper hearin' him tell about horse-race gamblin'. One fine night, they leave the pool hall, headin' for the dance at the Arm'ry! Libertine men and scarlet women, and ragtime, shameless music that'll grab your son and your daughter with the arms of a jungle animal instinct: mass-steria!

Usage and history

While examples of usage in the modern, metaphorical sense can be found in the early 1900s, its use as a common element in American political rhetoric emerged in the 1970s and gathered momentum in the 1980s. It does not seem to have had any specific connection to any single issue. Its first appearance in a New York Times article title was in 1969, "Russia and China Edge Down a Slippery Slope." Headline examples from the 1980s include "On the Slippery Slope To Another Vietnam," "Italy's Communists on Slippery Slope," "The Cheap Dollar's Slippery Slope," etc.

In a 2002 analysis, WIlliam Safire wrote:

The key task of the phrasedick is to find earliest uses of ["slippery slope"] in its present sense of "a course that leads inexorably to disaster." The OED tracks it to a 1951 novel, but new retrieval technology lets us do better than that.... we have this 1857 use from Chambers' Journal: "When the educated person of the middle class is reduced to pennilessness... what but this gives him the desire to struggle again up the slippery slope of fortune?"

In both of these citations, the meaning is closer to "the greasy pole...." The current sense... probably surfaced in the early 20th century, possibly in an article by a writer in a 1909 Quarterly Review, published in London: "the first step down that slippery slope at the bottom of which lies a parliamentary government."

—William Safire, 2002

Quotations illustrating use

Literal

Even when I was on this mare, she would poise herself on the top of a block of granite, with her four feet close together in the manner of a goat and she leaped across crevasses of unknown depth after having to go down a slippery slope on one side, and when, on the other, she had nothing to jump upon except steeply-inclined blocks of stone.—"Himalayan Ponies," The New York Times, March 14, 1875, p. 4

They stood, who saw the future come

On through the fight’s delirium!

They smote and stood, who held the hope

Of nations on that slippery slope

Amid the cheers of Christendom.

Will Henry Thompson (1888), "The High Tide at Gettyburg"

Metaphorical

It is not with them we are concerned: they will not be taught or reformed; so, they will go down the steep and slippery slope on which the heartless move, to perdition!

—Bernard O'Reilly, 1878

Is there one among us who is tempting a brother man to dishonesty, to drink, to lust; who is pushing some thoughtless girl down the steep and slippery slope which ends--we know where? Then let him stop and listen, not to me, but to Christ.

George Jackson (1903), The Teachings of Jesus

The cry for the rates in addition to the taxes has been going up from the clerical for years. But they were warned by the late Archbishop of Canterbury not to attempt it, for as surely as they succeeded they would lose their control of their sectarian schools. They would be on the "slippery slope," he said, in a characteristic phrase. However, they have taken the plunge, and the Education Acts of 1902 and 1903 are the results.

—John Clifford, 1905

We cannot give up any portion of our claim until the question of interallied debts has been settled. We have the right and duty to guarantee ourselves against the possibility of a diminution of our claim by the international financiers.... If today Germany obtained any remission of her debt she would profit.... It was by far the wisest policy to hold fast at the top of that slippery slope."

—French premier Raymond Poincaré, Nov. 16, 1923

Slope to perdition

The modern phrase, used seriously in a political or social context is simply slippery slope. The phrase "slippery slope to perdition" is also seen, but is usually ironic, as in a recent book on programming:

A parser that writes code, even if the code is only an occasional semicolon, seems like the beginning of a slippery slope to perdition. Pretty soon the Maple interface will behave like the Evil Empire's flagship word-processor, which tries to write for its unfortunate users.

The 1800s provide examples of serious rhetoric using the phrase "slope to perdition." Sometimes the slope is "slippery;" in other cases the word is not used but the context ("headlong slope to perdition") implies it. An example from 1837:

There are points where the Christian must always stand on guard. His danger is seldom found in gross offenses... but in small indulgences, and weak compliances, where conscience rather doubts, than condemns. These gradually draw him nearer and nearer to the world, till the line of separation is lost. Many a Christian has glided down this slope to perdition.

See also

• False Dilemma
• Non Causa Pro Causa