ABSTRACT
These conceptual tensions in Hanson’s approach to epistemology and philosophy of science have remained a particularly striking feature of much subsequent work in the field. Very often they have emerged through the doubts and misgivings that typically assail erstwhile realists when confronted with just the kinds of argument that Hanson brings to bear. Thus when Hilary Putnam famously announced his conversion from ‘metaphysical’ to ‘internal’ realism during his 1978 Presidential Address to the American Philosophical Association it was largely on account of the intractable problem – as he now saw it – with meeting the standard sceptical argument against any version of the stronger claim.1 For if truth is conceived, in objectivist terms, as requiring that our statements, beliefs, or theoretical commitments somehow match up with an order of ‘recognition-transcendent’ reality then surely this entails that we can never know whether they are true or false, or be in a position to grasp their operative truthconditions. Much better – Putnam now thought – to adopt a more sophisticated version of the verificationist approach and give up the delusive ‘metaphysical’ idea that truth could conceivably be anything more than a matter of optimal epistemic warrant or idealised rational acceptability. That is to say, we are not restricted (as an old-style verificationist would have it) to the evidence provided by our current-best range of observational data and the various higher-level theories, hypotheses, or covering-law statements from which those data can be shown to derive as a matter of strict deductive entailment.2 Rather, there is always an appeal open to what would (counterfactually) pass the test of warranted assertibility if all the evidence were in and subject to testing under optimal conditions by an ideally qualified community of expert investigators.
