Jarrett Leplin

The Underdetermination of Total Theories

This paper criticizes the attempt to found the epistemological doctrine that all theories are evidentially underdetermined on the thesis that all theories have empirically equivalent rivals. The criticisms focus on the role of auxiliary hypotheses in prediction. It is argued, in particular, that if auxiliaries are underdetermined, then the thesis of empirical equivalence is undecidable. The inference from empirical equivalence to the underdetermination of total theories would seem to survive the criticisms, because total theories do not require auxiliaries to yield observational consequences. It is shown that, nevertheless, underdetermination cannot be established for total theories.

The Bearing of Discovery on Justification

The point of the traditional distinction between the contexts of discovery and justification is to insist on the normative character of epistemology. The point is not to dismiss from epistemology merely the genesis of ideas; into the context of discovery go also descriptions of evaluative practices and decisions. However ideas are created, scrutinized, and judged, it is only the approbation to which they are entitled, accorded or not, that allegedly matters to epistemology. The criticism, familiar since N.R. Hansons Patterns of Discovery,1 that philosophy ought not to ignore the genesis of ideas is ironically conservative. If what is not normative epistemology is to be ignored, then the distinction would have us ignore even the reception and appraisal of scientific ideas.

Theoretical identification and the mind-body problem

I The natural and popular response of proponents of event-identity materialism (ELM) to Kripkes refutation of the contingency of true identity statements whose terms are rigid designators I is to assume that sensations are distinguishable from their appearances) Given such distinguishability, reference to sensations is fixed by their contingent properties, and the necessity of their identification with physical events is reconciled with the apparent ability to imagine the occurrence of an event of either type without the occurrence of an event of the other. For it can be claimed that what is really imagined is that-the appearance of a sensation is the appearance of something else, or that a sensation occurs without appearing to. Given the contingency of the relation between a sensation and its appearance, such imaginings need be no more problematic than other, more familiar counterfactuals. This approach has the advantage of preserving the analogy with standard scientific identifications to which the plausibility of materialist identity theories has traditionally been entrusted. For, i t is said, we now recognize that the significance of the water H2 O, lightning electric discharge, heat molecular motion, (etc.) examples is to demonstrate not that identity can be contingent but that it can be a posteriori. And aposteriority is consistent with necessity