Consider the following premises. For all z, z is a server if and only if z is an astronaut. For all z, z is a server if and only if z is an astronaut. Can we infer the following from them? If Thomas were a server, then Thomas is an astronaut.
 From the fact that for all z, z is a server if and only if z is an astronaut we can infer that for all z, if z were an astronaut, then z is a server. From the fact that for all z, z is a server if and only if z is an astronaut we can infer that for all z, if z were a server, then z is an astronaut. From the fact that for all z, if z were an astronaut, then z is a server, and that for all z, if z were a server, then z is an astronaut we can infer that for all z, z is an astronaut if and only if z is a server. From the fact that for all z, z is an astronaut if and only if z is a server we can infer that Thomas is an astronaut if and only if Thomas is a server. Finally, from the fact that Thomas is an astronaut if and only if Thomas is a server we can infer that if Thomas were a server, then Thomas is an astronaut. Therefore, the answer is yes.