 Various attempts have been made to salvage the argument. Against the first of these considerations it has been pointed out that we successfully appeal to analogy when extending our knowledge from the present to the past. However, Hyslop and Jackson (1972) remind us that this defense fails to register the fact that the impossibility of checking the conclusion in the case of other minds is logical (cf.  §1),  and prefer to defend appeal to analogy here by suggesting that, while this is true, it is not “obviously relevant”. They also suggest that the fact that the conclusion here cannot be verified may be “neutralized” by the fact that it also cannot be refuted (1972: 169–170).