Consider the following premises. For all x_14, if x_14 were a writer, then x_14 is a musician. William is not a musician. Can we infer the following from them? William is a writer.
 From the fact that for all x_14, if x_14 were a writer, then x_14 is a musician we can infer that if William were a writer, then William is a musician. Finally, from the fact that if William were a writer, then William is a musician, and that William is not a musician we can infer that William is not a writer, which contradicts that William is a writer. Therefore, the answer is no.