Consider the following premises. Joseph is an astronaut. For all y, y is a poet. Can we infer the following from them? For all y, either y is a poet or y is an astronaut are not true.
 From the fact that Joseph is an astronaut we can infer that there is at least one y for which y is an astronaut. Finally, from the fact that for all y, y is a poet, and that there is at least one y for which y is an astronaut we can infer that there is at least one y for which y is a poet and y is an astronaut, which contradicts that For all y, either y is a poet or y is an astronaut are not true. Therefore, the answer is no.