Debates on euthanasia, abortion or embryonic stem cell research frequently invoke slippery slope arguments. Here is an example of such reasoning:
Legalizing physician-assisted suicide (PAS) at the end of life pushes healthcare morality in a dangerous direction. Soon, PAS may be practiced even on people who are not at the end of life and who do not request it. Even if this does not happen, the general population’s trust in healthcare will erode. Therefore, PAS must be forbidden.
Reasoning about the future is important. We need to assess consequences of allowing new practices. However, how do we assess the future in a credible way?
In an article in Medicine, Health Care and Philosophy, Gert Helgesson, Niels Lynøe and Niklas Juth argue that many slippery slope arguments are not empirically substantiated, but are based on value-impregnated factual assumptions. Anyone who considers PAS absolutely wrong considers it as a fatal step in a dangerous direction. Therefore, it is assumed that taking such a step will be followed by further steps in the same dangerous direction. If you chose the wrong path, you end up further and further away in the wrong direction. It seems inevitable that a first step is followed by a second step…
The problem is that this prophesying is based on the original moral interpretation. Anyone who is not convinced of the fatality of a “first” step does not have a tendency to see it as a “first step” with an inherent tendency to lead to a “second step” and finally to disaster.
Thinking in terms of the slippery slope can sometimes be experienced as if you yourself were on the slippery slope. Your thoughts slide toward the daunting precipice. Perhaps the article by Helgesson, Lynøe and Juth contains an analysis of this phenomenon. The slippery slope has become a vicious circle where the prophesying of disastrous consequences is steered by the moral interpretation that one defends with reference to the slippery slope.
Slippery slope arguments are not wrong in themselves. Sometimes development is on a slippery slope. However, this form of reasoning requires caution, for sometimes it is our thoughts that slide down along the slippery slope.
And that can have consequences.
Helgesson, G., Lynøe, N., Juth, N. 2017. Value-impregnated factual Claims and slippery slope arguments. Medicine, Health Care and Philosophy 20: 147-150.