Least convenient possible world
The "Least Convenient Possible World" is a tool of intellectual honesty, to be used when arguing against an idea.
The essence of the principle is to, when disputing a general argument, assume that all specific details will align with the argument, i.e., the least convenient possible world in which to make your counterargument. If this world is so unlikely as to be all but impossible, accept the validity of the argument and instead dispute its applicability to the real world.
The Least Convenient Possible World on Less Wrong