Consider the following premises. It is windy if and only if Robert is a lawyer. It is windy if and only if Robert is a lawyer. Can we infer the following from them? Robert is a lawyer if and only if it is windy.
 From the fact that it is windy if and only if Robert is a lawyer we can infer that if Robert were a lawyer, then it is windy. From the fact that it is windy if and only if Robert is a lawyer we can infer that if it is windy, then Robert is a lawyer. Finally, from the fact that if Robert were a lawyer, then it is windy, and that if it is windy, then Robert is a lawyer we can infer that Robert is a lawyer if and only if it is windy. Therefore, the answer is yes.