The slippery slope argument asserts that the initial step taken is a precursor to a chain of events that eventually lead to undesirable or disastrous results. Thus, the course of action is rejected. The slippery slope is often view as a logical fallacy because the trajectory of actions tends to be assumption based. It is acknowledged that non-fallacious forms of the argument can exist given the proper rigor of evidence-based conclusions between each step.

There are two basic types of slippery slope arguments. The causal slippery slope states that each step is the cause of the next step. The judgmental slippery slope is as one would expect, one judgement leads to making a second judgment. For example, a person decides to steal, which leads to aggravated assault and eventually to murder.

Highly illogical argument

There are numerous alternatives and metaphors associated with this fallacy.

Thin End of a Wedge

Alfred Sidgwick is often credited as the first writer to describe a slippery slope argument. The metaphor captures the idea that the action or decision present in the initial step is more widely applied as the argument progresses.

For example, if we allow the government to oversee healthcare, they will decide what procedures we can have. They will set up death panels to determine when you are too old or too sick to warrant healthcare. This was a popular misinformation campaign run during the Obamacare debates in the United States. The fallacy here is each step needs to be passed as law and ratified by both congress and the senate. It is unusual for a party to control the presidency, the senate and congress at one time. Additionally, the setup of death panels would violate the US constitution and surely be repealed by the Supreme Court.

Domino Fallacy

T. Edward Damer prefers to call the slippery slope theory the domino fallacy. It is a helpful metaphor describing one event leading to another and continuing until the end game is reached. Perhaps the most famous application of this fallacy relates to Domino Theory that was wielded by the U.S. government in the forties and fifties in describing the spread of communism. As each successive country fell to communist rule another domino tipped.

A pandemic might fit as a better example of domino effect. However, there are decisions that can be made to prevent the next domino from falling. Timing is crucial in this scenario. The dominos will tip if governments do not issue stay at home orders soon enough or if they re-open too early. Taiwan, South Korea, and Singapore are shining examples of making timely, effective decisions that stopped the chain of events.

Dam Burst

The dam burst metaphor grew out of the German-speaking world as a more spectacular interpretation of the slippery slope argument with the most attention applied to the initial event. Subsequent events or consequences are non-linear and rapid, and it comes across that there are no further decision points.

Again, the Covid-19 pandemic is a good example. The explosion of the virus quickly led to economic shutdowns, massive job loss, huge accumulation of national debts and a raft of misinformation. The fallout of the pandemic was swift, and countries were given few choices on responding.

Boiling Frog

The boiling frog metaphor is most famous from Daniel Quinn’s The Story of B. If you drop a frog in boiling water, it will try frantically to escape. However, placing the frog in tepid water and slowly heating it causes the frog to fall into a stupor and unknowingly let itself be boiled to death. The analogy implies one is unaware of how bad a situation has become because it happened slowly, and the time has passed to take corrective action.

The perfect application of this metaphor is its use with climate change. Unfortunately, humanity is the frog in this example.

Snowball Effect

Metaphorically, the snowball effect starts small and increases in size as it rolls down a snow-covered mountain. With more surface area to pick up more snow on each revolution growth becomes exponential, assuming the slope is constant. There are only a few cases where using the snowball effect is logical.

Invasive species, untreated cancer cells, human population, uncontrolled pandemics are real-life examples of exponential growth. Apparently, we need to re-examine the company we keep. A positive example of exponential growth is compound interest. Start saving today.

Applying the snowball effect against decision or policy making would be hyperbole in most cases as measuring impacts of each step on the subsequent one is typically unattainable.

Broken Windows Theory

The Broken Windows theory states that visible signs of disorder and misbehavior in an environment encourage further disorder and misbehavior, leading to serious crimes. In 1969, Philip Zimbardo, a psychologist from Stanford University did a field study. He abandoned a car in a crime-ridden neighborhood in New York. The car was quickly stripped for parts. He did the same in a more affluent neighborhood in Los Angeles and it was untouched for more than a week. He then took a sledgehammer to the car. It was stripped of parts shortly after his damaging body work. First introduced in 1982 by social scientists the broken windows theory was later put into practice most famously by Rudy Giuliani as the Mayor of New York in the 1990s.

Giuliani’s use of the theory led to a sharp decline in major crime and he cruised to re-election. A closer examination suggests he simply had good timing. Stockbrokers are familiar with the term regression to the mean, which says if something increases a lot it will later decrease a lot. Crime is similar and it coincidentally (or not) also dropped in cities not implementing broken windows theory around the time of Giuliani’s implementation. Today, big data and business intelligence could give us a better picture into what data tells us. Is it correlation or causation?

How does this relate to the slippery slope fallacy? The apparent success of broken windows theory led to stop and frisk, which was an unmitigated disaster possibly violating constitutional reasonable search law and it used racial profiling. Part of the broken windows theory focused on fair jumpers on the New York City subway. By their own findings, most criminals where fare jumpers. However, most fare jumpers were not criminals. The leap from broken windows to stop and frisk was counter to this finding and is a perfect example of slippery slope playing out as feared. While many times the illogical leap between events on a slippery slope is why it is a fallacy. This time, it was an illogical step that led to the feared unintended consequences.

All this said, broken windows theory is an intriguing study in human behavior. Does this one instance suggest we should not simply cite the slippery slope fallacy?

The Butterfly Effect

The butterfly effect may be one of the most intriguing metaphors related to the slippery slope argument. The concept is attributed to the work of Edward Lorenz in the 1950s. A meteorologist and mathematician who discovered it by mistake while trying to create models to predict the weather. His simple metaphor was a butterfly flaps its wings and alters the path of a typhoon.

Scientifically speaking, it aligns with chaos theory that is maybe best defined by Discover Magazine in the April 2007 edition as a mathematical way of determining the effects of small changes on systems so complex they look random. Beyond being an out for the weatherman, the butterfly effect is also used to describe the stock market and economics.

Its application to time travel is even more intriguing and the concept has inspired many movies and books, including Ray Bradbury’s classic A Sound of Thunder, and Steven King’s 11/22/63.

First They Came

This metaphor comes from German Lutheran pastor Martin Niemöller after the fall of Nazi Germany. It is a poetic form confession that has similarities to the slippery slope argument. Unfortunately, the argument was true. Here is the text quoted at the United States Holocaust Museum.

First they came for the socialists, and I did not speak out -
Because I was not a socialist.
Then they came for the trade unionists, and I did not speak out -
Because I was not a trade unionist.
Then they came for the Jews, and I did not speak out -
Because I was not a Jew.
Then they came for me - and there was no one left to speak for me.

The bitter divide in the United States since 2008 often invokes this historic example by the side not in power. Fear is a great motivator, and most can not imagine a society worse than Nazi Germany.

Gateway Drug Theory

The gateway drug theory is another example of slippery slope that suggests an initial action, smoking cannabis, leads to more serious consequences. In this case, the use of harder drugs such as heroin or cocaine.

Wikipedia’s coverage of the theory shows forty-seven citations of studies surrounding cannabis as a gateway drug. The studies raise an interesting question of what percentage of the population taking the next step validates causation? Most first-time users do not move on to other drugs. The data suggests that the appearance of cannabis as a gateway drug is hidden by other social, psychological, and genetic factors.

More info: