Consider the following premises. For all x_6, x_6 is an office clerk or x_6 will not climb a mountain. For all x_6, x_6 will climb a mountain. There is at least one x_6 for which if x_6 were a carpenter, then x_6 is not an office clerk. Can we infer the following from them? There is at least one x_6 for which x_6 is not a carpenter.
 From the fact that for all x_6, x_6 is an office clerk or x_6 will not climb a mountain we can infer that for all x_6, if x_6 climbs a mountain, then x_6 is an office clerk. From the fact that for all x_6, if x_6 climbs a mountain, then x_6 is an office clerk, and that for all x_6, x_6 will climb a mountain we can infer that for all x_6, x_6 is an office clerk. Finally, from the fact that there is at least one x_6 for which if x_6 were a carpenter, then x_6 is not an office clerk, and that for all x_6, x_6 is an office clerk we can infer that there is at least one x_6 for which x_6 is not a carpenter. Therefore, the answer is yes.