Fallacies
Conflicting Conditions

 Definition 

The definition is self-contradictory.

 Explanation 

None needed.

 Examples 

A society is free if and only if liberty is maximized and people are required to take responsibility for their actions.
Definitions of this sort are fairly common, especially on the internet. However, if a person is required to do something, then that person's liberty is not maximized.

People are eligible to apply for a learner's permit (to drive) if they have (a) no previous driving experience, (b) access to a vehicle, and (c) experience operating a motor vehicle.
A person cannot have experience operating a motor vehicle if they have no previous driving experience.

 Counter-examples 

None.

 Advices 

Identify the conditions in the definition. Show that they cannot all be true at the same time (in particular, assume that one of the conditions is true, then show from this that another of the conditions must be false).