Consider the following premises. For all x_17, if x_17 takes a plane, then x_17 is playing tennis. For all x_17, if x_17 climbs a mountain, then x_17 is taking a plane. For all x_17, x_17 is a writer if and only if x_17 will play tennis. There is at least one x_17 for which x_17 will climb a mountain. Can we infer the following from them? For all x_17, x_17 is not a writer.
 From the fact that for all x_17, x_17 is a writer if and only if x_17 will play tennis we can infer that for all x_17, if x_17 plays tennis, then x_17 is a writer. From the fact that for all x_17, if x_17 takes a plane, then x_17 is playing tennis, and that for all x_17, if x_17 plays tennis, then x_17 is a writer we can infer that for all x_17, if x_17 takes a plane, then x_17 is a writer. From the fact that for all x_17, if x_17 climbs a mountain, then x_17 is taking a plane, and that there is at least one x_17 for which x_17 will climb a mountain we can infer that there is at least one x_17 for which x_17 will take a plane. Finally, from the fact that for all x_17, if x_17 takes a plane, then x_17 is a writer, and that there is at least one x_17 for which x_17 will take a plane we can infer that there is at least one x_17 for which x_17 is a writer, which contradicts that For all x_17, x_17 is not a writer. Therefore, the answer is no.