If you do A, then B will certainly happen, because I say it.
Source, Wikipedia
The slippery slope fallacy is one of the common informal fallacies. It suggests that an action will trigger a chain of events and culminate in a subsequent unwanted event, without establishing nor quantifying the relevant contingencies. This argument is also known as “the domino effect”. A long series of intermediate events is usually offered as the connecting device from A to B, from an apparently harmless start to a completely undesirable end. This fallacy takes for granted uncertain -and sometimes not even likely- consequences.
Example
If we let children eat improperly at the table, they will end up becoming criminals, since they won’t assimilate an adequate code of conduct.
To refute it
A slippery slope could be true, but it will be a fallacy if what it claims doesn’t have a well established cause-effect link. Therefore, if whoever is making the claim is not providing that data, it should only be necessary to point out this fact in order to refute it. Since it usually follows a series of steps from the beginning of the slope, at the end of the day it just takes one of those steps to break in order to deny the claim.
Whenever the source is not referenced, both definitions and examples have been extracted from a translation of Jaime Wilson jwilson@bytecr.com based on Stephen’s Guide to the Logical Fallacies. Copyright 1995-1998 Stephen Downes. Brandon, Manitoba, Canada.
These texts have been modified by Miguel A. Lerma and now by us to adapt them -and those taken from Wikipedia- to our format.