Question

Converse accident, destroying the exception

Accepted Answer

An exception to a generalization is applied to cases where the generalization should apply. When an exception to a generalization is wrongly called for.

When an attempt is made to apply a general rule to all situations, when clearly there are exceptions to the rule. Simplistic rules or laws rarely take into consideration legitimate exceptions, and to ignore these exceptions is to bypass reason to preserve the illusion of a perfect law. People like simplicity and would often rather keep simplicity at the cost of rationality.

Examples:
Because we allow terminally ill patients to use heroin, we should allow everyone to use heroin.
Because you allowed Jill, who was hit by a truck, to hand in her assignment late, you should allow the entire class to hand in their assignments late.
Proof:
Identify the generalization in question and show how the special case was an exception to the generalization.

If we allow people with glaucoma to use medical marijuana, then everyone should be allowed to use marijuana.

The inductive version of this fallacy is called hasty generalization. See faulty generalization.

This fallacy is similar to the slippery slope, where the opposition claims that if a restricted action under debate is allowed, such as allowing people with glaucoma to use medical marijuana, then the action will by stages become acceptable in general, such as eventually everyone being allowed to use marijuana. The two arguments imply there is no difference between the exception and the rule, and in fact fallacious slippery slope arguments often use the converse accident to the contrary as the basis for the argument. However, a key difference between the two is the point and position being argued. The above argument using converse accident is an argument for full legal use of marijuana given that glaucoma patients use it. The argument based on the slippery slope argues against medicinal use of marijuana because it will lead to full use.

The opposing kind of dicto simpliciter is accident.

Exception Generalization Converse People Allowed Glaucoma Slippery Argument