The argument stating, "All working registered nurses in this hospital have passed state boards. Marian has passed the state boards. She is therefore working in this hospital" is an example of ______.

• A. a valid argument
• B. a circular argument
• C. an invalid argument
• D. an ambiguous argument

Answer: (C)

The argument presented is an example of an invalid argument because it makes a leap in logic that is not warranted by the premises given. The initial statement establishes that all working registered nurses in the hospital have passed the state boards, which creates a specific condition for nurses who work there. However, the conclusion drawn—that because Marian has passed the state boards she must therefore be working in this hospital—is flawed because it does not account for the possibility of registered nurses who have passed the state boards but are not employed by this particular hospital. In other words, just because someone has met a requirement does not mean they fulfill all conditions necessary for the conclusion to be true.

The qualifications of the premise do not support the conclusion, demonstrating a breakdown in logical reasoning, thus categorizing the argument as invalid. Understanding this distinction is crucial in the study of formal logic and critical thinking, especially in evaluating the strength of arguments in spoken and written communication.