How do we know our right hand from our left hand when there is literally nothing that can be said about one which cannot be said about the other?
Two important historical discussions of this problem. First, Leibniz in the Third Letter to Clarke, par.5. Interestingly, Leibniz asks whether the entire cosmos could be reversed (its handedness changed). Second, Kant, Prolegomena , par. 13, where he calls handed object 'incongruent counterparts'. In both cases, the question is on what grounds, if any, the distinction could be made.