Consider the following premises. James is a nurse if and only if James is an office clerk. James is not an office clerk. For all x_12, if x_12 were an office clerk, then x_12 is a nurse. Can we infer the following from them? James is not a nurse.
 From the fact that for all x_12, if x_12 were an office clerk, then x_12 is a nurse we can infer that if James were an office clerk, then James is a nurse. From the fact that James is a nurse if and only if James is an office clerk we can infer that if James were a nurse, then James is an office clerk. From the fact that if James were an office clerk, then James is a nurse, and that if James were a nurse, then James is an office clerk we can infer that James is an office clerk if and only if James is a nurse. Finally, from the fact that James is an office clerk if and only if James is a nurse, and that James is not an office clerk we can infer that James is not a nurse. Therefore, the answer is yes.