Reply to Solomon

Abstract

The first objection appeals to the familiar idea that theories are underdetermined by evidence. Solomon argues that there will always be many possible alternative and incompatible systems of belief which satisfy all of the coherentist justificatory constraints to which the metajustificatory argument appeals, i.e. which are equally coherent, satisfy the observation requirement, and remain stable over time. Since these different systems cannot all be likely to be true in the realist sense of truth invoked by the argument, the argument must fail. I think that Solomon is right that some degree of underdetermination is unavoidable, that different systems of belief that are logically incompatible with each other may be equally justified. But how a serious a problem this poses for the metajustificatory argument will depend on how radical the underdetermination is, i.e. on how far such alternative systems of belief diverge from each other. If the divergence is small enough, if the different alternatives are in effect close variations on a common theme, then it will still be possible to say, invoking a familiar notion from discussions in the philosophy of science, that a system that satisfies the justificatory constraints is likely to be at least approximately true and this seems to me enough to save the basic thrust of the argument. The intelligibility of the concept of approximate truth has sometimes been challenged, but I think that we can do well enough for present purposes by saying that a belief is approximately true if a vaguer, less specific