Consider the following premises. There is at least one x_7 for which x_7 is a scientist if and only if x_7 is a cashier. For all x_7, x_7 is a police officer if and only if x_7 is a lawyer. For all x_7, if x_7 were a cashier, then x_7 is a lawyer. For all x_7, x_7 is not a police officer. Can we infer the following from them? There is at least one x_7 for which x_7 is not a scientist.
 From the fact that for all x_7, x_7 is a police officer if and only if x_7 is a lawyer, and that for all x_7, x_7 is not a police officer we can infer that for all x_7, x_7 is not a lawyer. From the fact that for all x_7, if x_7 were a cashier, then x_7 is a lawyer, and that for all x_7, x_7 is not a lawyer we can infer that for all x_7, x_7 is not a cashier. Finally, from the fact that there is at least one x_7 for which x_7 is a scientist if and only if x_7 is a cashier, and that for all x_7, x_7 is not a cashier we can infer that there is at least one x_7 for which x_7 is not a scientist. Therefore, the answer is yes.