Future studies is an emerging academic discipline to rigorously examine claims about the future. It is epistemological in that it centralises the arguments about what is knowable. It makes the distinctions between what is possible, what is probable and what is desirable.
It is cross disciplinary and draws on established traditions such as analytic philosophy and mathematics to evaluate applicability and probability.
Another explanation is to imagine a sociology about a world that doesn't exist. You can still apply the same critical rigour to arguments about such a fictitious world. Now imagine that as time progresses, evidence about that fictitious world becomes observable in a verifiable way and that (hitherto counterfactual) arguments are now falsifiable. This would then form a credible domain for discourse which can be peer-reviewed.