Consider the following premises. For all x_18, x_18 is not a taxi driver. For all x_18, x_18 will sleep if and only if x_18 is a sailor. Susan is fast if and only if William is a sailor. Susan is fast or Michael is an office clerk. For all x_18, x_18 will sleep if and only if x_18 is a taxi driver. Can we infer the following from them? Michael is an office clerk.
 From the fact that for all x_18, x_18 will sleep if and only if x_18 is a taxi driver, and that for all x_18, x_18 is not a taxi driver we can infer that for all x_18, x_18 will not sleep. From the fact that for all x_18, x_18 will sleep if and only if x_18 is a sailor, and that for all x_18, x_18 will not sleep we can infer that for all x_18, x_18 is not a sailor. From the fact that for all x_18, x_18 is not a sailor we can infer that William is not a sailor. From the fact that Susan is fast if and only if William is a sailor, and that William is not a sailor we can infer that Susan is not fast. Finally, from the fact that Susan is fast or Michael is an office clerk, and that Susan is not fast we can infer that Michael is an office clerk. Therefore, the answer is yes.