Consider the following premises. For all x, if x were a scientist, then x is a soldier. For all x, x is sad or x is a doctor. For all x, x is a doctor if and only if x is a soldier. There is at least one x for which if x were sad, then x is a scientist. Can we infer the following from them? For all x, x is not a soldier.
 From the fact that for all x, x is a doctor if and only if x is a soldier we can infer that for all x, if x were a doctor, then x is a soldier. From the fact that there is at least one x for which if x were sad, then x is a scientist, and that for all x, if x were a scientist, then x is a soldier we can infer that there is at least one x for which if x were sad, then x is a soldier. Finally, from the fact that there is at least one x for which if x were sad, then x is a soldier, that for all x, if x were a doctor, then x is a soldier, and that for all x, x is sad or x is a doctor we can infer that there is at least one x for which x is a soldier, which contradicts that For all x, x is not a soldier. Therefore, the answer is no.