In
logic and
critical thinking, a
slippery slope is a logical device, but it is usually known under its fallacious form, in which a person asserts that some event must inevitably follow from another without any rational argument or demonstrable mechanism for the inevitability of the event in question. A slippery slope argument states that a relatively small first step leads to a
chain of related events culminating in some significant effect, much like an object given a small push over the edge of a slope sliding all the way to the bottom.
[1] The strength of such an argument depends on the
warrant, i.e. whether or not one can demonstrate a process that leads to the significant effect. The fallacious sense of "slippery slope" is often used synonymously with
continuum fallacy, in that it ignores the possibility of middle ground and assumes a discrete transition from category A to category B. Modern usage avoids the fallacy by acknowledging the possibility of this middle ground.