Kahane says, "The slippery slope fallacy is committed only when we accept without further justification or argument that once the first step is taken, the others are going to follow, or that whatever would justify the first step would in fact justify the rest."
[9] The problem then arises as to how to evaluate the likelihood that certain steps would follow.
Volokh's article "The Mechanisms of the Slippery Slope"
[24] sets out to examine the various ways in which making one decision might render another decision more likely. He considers such things as implementing A making B more cost effective and implementing A changing attitudes such that acceptance of B will become more likely. He says, "If you are faced with the pragmatic question "Does it make sense for me to support A, given that it might lead others to support B?," you should consider all the mechanisms through which A might lead to B, whether they are logical or psychological, judicial or legislative, gradual or sudden ... You should think about the entire range of possible ways that A can change the conditions—whether those conditions are public attitudes, political alignments, costs and benefits, or what have you—under which others will consider B."
[24]:1030–1031
Volokh concludes by claiming that the analysis in his article "implicitly rebuts the argument that slippery slope arguments are inherently logically fallacious: the claim that A's will inevitably lead to B's as a matter of logical compulsion might be mistaken, but the more modest claim that A's may make B's more likely seems plausible."
[24]:1134 A similar conclusion was reached by Corner et al., who after investigating the psychological mechanism of the slippery slope argument say, "Despite their philosophical notoriety, SSAs are used (and seem to be accepted) in a wide variety of practical contexts. The experimental evidence reported in this paper suggests that in some circumstances, their practical acceptability can be justified, not just because the decision-theoretic framework renders them subjectively rational, but also because it is demonstrated how, objectively, the slippery slopes they claim do in fact exist.