This is a new epistemological approach to the inexact sciences. The purpose of all science is to explain and predict in an objective manner. While in the exact sciences explanation and prediction have the same logical structure, this is not so in the inexact sciences. This permits various methodological innovations in the inexact sciences, e.g., expert judgment and simulation.

The main object of this paper is to provide the logical machinery needed for a viable basis for talking of the 'consequences', the 'content', or of 'equivalences' between inconsistent sets of premisses.With reference to its maximal consistent subsets (m.c.s.), two kinds of'consequences' of a propositional set S are defined. A proposition P is a weak consequence (W-consequence) of S if it is a logical consequence of at least one m.c.s, of S, and P is an inevitable consequence (/-consequence) of S if it is a logical consequence of all the m.c.s. of S. The set of W-consequences of a set S it determines (up to logical equivalence) its m.c.s. (This enables us to define a normal form for every set such that any two sets having the same W-consequences have the same normal form.) The W-consequences and/-consequences will not do to define the 'content' of a set S. The first is too broad, may include propositions mutually inconsistent, the second is too narrow. A via media between these concepts is accordingly defined: P is a P-consequence of S, where P is some preference criterion yielding some of the m.c.s, of S as preferred to others, and P is a consequence of all of the P-preferred m.c.s, of S. The bulk of the paper is devoted to discussion of various preference criteria, and also surveys the application of this machinery in diverse contexts -for example, in connection with the processing of mutually inconsistent reports.

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r greater than at present. Or possibly, a decision was made on presumed suburban reliance on automobile transport because of greater affluence; that could have the effect of a selffulfilling prophecy. In any event, decisions are made, if not done out of negligence, for reasons. To decide between the two analyses, one would want to ask the reasons for the original deCision for the present level of service. If City Hall made a * 15 * potential usage study, the citizens are guilty of a Contrary-to-Fact fallacy. If no such study was made, there would not appear to be an~ fallacy--not as the argument is stated, 1n any event.