Consider the following premises. James is an electrician or John is not climbing a mountain. James is an electrician if and only if John is climbing a mountain. Can we infer the following from them? The fact that James were an electrician does not imply that John is climbing a mountain.
 From the fact that James is an electrician or John is not climbing a mountain we can infer that if John climbs a mountain, then James is an electrician. Finally, from the fact that James is an electrician if and only if John is climbing a mountain we can infer that if James were an electrician, then John is climbing a mountain, which contradicts that The fact that James were an electrician does not imply that John is climbing a mountain. Therefore, the answer is no.