Consider the following premises. For all x_12, x_12 is an astronaut. For all x_12, x_12 is not sad or x_12 is an office clerk. For all x_12, x_12 is sad or x_12 is a bartender. For all x_12, x_12 is not a bartender or x_12 will write a letter. There is at least one x_12 for which if x_12 were an office clerk, then x_12 is not an astronaut. Can we infer the following from them? There is at least one x_12 for which x_12 will write a letter.
 From the fact that for all x_12, x_12 is sad or x_12 is a bartender, and that for all x_12, x_12 is not sad or x_12 is an office clerk we can infer that for all x_12, x_12 is a bartender or x_12 is an office clerk. From the fact that there is at least one x_12 for which if x_12 were an office clerk, then x_12 is not an astronaut, and that for all x_12, x_12 is an astronaut we can infer that there is at least one x_12 for which x_12 is not an office clerk. From the fact that for all x_12, x_12 is a bartender or x_12 is an office clerk, and that for all x_12, x_12 is not a bartender or x_12 will write a letter we can infer that for all x_12, x_12 is an office clerk or x_12 will write a letter. Finally, from the fact that for all x_12, x_12 is an office clerk or x_12 will write a letter, and that there is at least one x_12 for which x_12 is not an office clerk we can infer that there is at least one x_12 for which x_12 will write a letter. Therefore, the answer is yes.