Consider the following premises. For all x_14, if x_14 were a writer, then x_14 is sleeping. There is at least one x_14 for which x_14 will write a letter if and only if x_14 is a writer. For all x_14, if x_14 sleeps, then x_14 is a writer. For all x_14, x_14 will not sleep. For all x_14, if x_14 writes a letter, then x_14 is a taxi driver. For all x_14, if x_14 were a taxi driver, then x_14 is writing a letter. Can we infer the following from them? There is at least one x_14 for which x_14 is not a taxi driver.
 From the fact that for all x_14, if x_14 sleeps, then x_14 is a writer, and that for all x_14, if x_14 were a writer, then x_14 is sleeping we can infer that for all x_14, x_14 will sleep if and only if x_14 is a writer. From the fact that for all x_14, x_14 will sleep if and only if x_14 is a writer, and that for all x_14, x_14 will not sleep we can infer that for all x_14, x_14 is not a writer. From the fact that for all x_14, if x_14 writes a letter, then x_14 is a taxi driver, and that for all x_14, if x_14 were a taxi driver, then x_14 is writing a letter we can infer that for all x_14, x_14 will write a letter if and only if x_14 is a taxi driver. From the fact that there is at least one x_14 for which x_14 will write a letter if and only if x_14 is a writer, and that for all x_14, x_14 is not a writer we can infer that there is at least one x_14 for which x_14 will not write a letter. Finally, from the fact that for all x_14, x_14 will write a letter if and only if x_14 is a taxi driver, and that there is at least one x_14 for which x_14 will not write a letter we can infer that there is at least one x_14 for which x_14 is not a taxi driver. Therefore, the answer is yes.