Essay | Understanding the Slippery Slope Fallacy

The slippery slope fallacy is a type of informal fallacy. In formal logic, it belongs to hypothetical syllogism, using a chain of causal inferences that exaggerates the causal strength in each link, turning “possibility” into “inevitability,” leading to unreasonable conclusions. However, events do not necessarily follow linear deductions, and there are other possibilities¹.

The typical form of the slippery slope fallacy is:

• If $A_1$ happens, then $A_2$ will happen, then $A_3$ will happen, then $A_4$ will happen, and so on up to $A_n$.
• Consequently, it usually implies or suggests: $A_n$ should not happen, therefore we should not allow $A_1$.

The causal relationships from $A_1$ to $A_2$, $A_2$ to $A_3$, etc., are like “slopes,” and the process of inferring from $A_1$ to $A_n$ is like a slippery slope.

The problem with the slippery slope fallacy is that the causal strength of each “slope” varies; some relationships are only possible, not inevitable; some are quite weak; some are unknown or lack evidence. If there is sufficient evidence showing that each “slope” has a reasonable and strong causal connection, it does not constitute a slippery slope fallacy.

For example, in the comments section of a TikTok video, people’s reactions to my comment can be analyzed in the typical form of the slippery slope fallacy:

1. $A_1$: I post a comment in the TikTok comments pointing out inaccuracies in the video: Huawei’s AI chip has made progress, but it hasn’t fully surpassed NVIDIA.
2. $A_2$: Some groups interpret this comment as me having a bias against domestic products.
3. $A_3$: These groups therefore infer that I don’t support Huawei or even China’s technological progress.
4. $A_4$: They further infer that this bias indicates I support foreign products or foreign viewpoints.
5. $A_n$: Ultimately, these people label me as a “public intellectual,” “traitor spy,” “slanderer of national industries,” etc., viewing me as someone opposing national and ethnic interests.

In this example, the causal relationships from $A_1$ to $A_n$ gradually weaken and are filled with assumptions and misinterpretations. These assumptions lack supporting evidence and are often based on emotional reactions rather than factual analysis.

• The causal link from $A_1$ to $A_2$ assumes that all criticism is negative, ignoring the possibility of constructive criticism.
• The connections from $A_2$ to $A_3$ and $A_3$ to $A_4$ are based on presumptions about my personal stance, not the content of my comment.
• Reaching $A_n$, labeling me as anti-national, is a huge logical leap with no actual evidence supporting this final negative label.

The challenge of slippery slope fallacies lies in their often hidden nature within seemingly logical coherence, making them hard to spot or refute immediately. Here are a few examples worth exploring in depth:

• If we continue to develop and rely on AI to perform daily tasks, human decision-making abilities will soon deteriorate. Over time, humans will become completely dependent on machines for every choice in life, ultimately leading to a loss of autonomy.
• If we don’t restrict inflammatory speech on the internet, it could gradually erode societal values, eventually leading to a complete collapse of social morality.

Slippery slope fallacies are insidious and challenging; they subtly guide us toward excessive or erroneous inferences. Even when expressing professional opinions, I might unintentionally adopt “if… then…” reasoning patterns, often overlooking the multiple possibilities and complexities of event development. I have always believed that continuous reflection and critique of one’s own thinking patterns are crucial. Therefore, I am recording this to remind myself that by understanding slippery slope fallacies, I can more clearly identify and avoid such cognitive pitfalls.