Consider the following premises. If Robert were a taxi driver, then Joseph is reading a book. If Thomas were a sailor, then Joseph is reading a book. If Joseph reads a book, then Robert is a taxi driver. Robert is not a taxi driver. Can we infer the following from them? Thomas is not a sailor.
 From the fact that if Robert were a taxi driver, then Joseph is reading a book, and that if Joseph reads a book, then Robert is a taxi driver we can infer that Robert is a taxi driver if and only if Joseph is reading a book. From the fact that Robert is a taxi driver if and only if Joseph is reading a book, and that Robert is not a taxi driver we can infer that Joseph is not reading a book. Finally, from the fact that if Thomas were a sailor, then Joseph is reading a book, and that Joseph is not reading a book we can infer that Thomas is not a sailor. Therefore, the answer is yes.