Gerald J. Massey

A bivalent valuation is snt iff sound (standard PC inference rules take truths only into truths) and non-trivial (not all wffs are assigned the same truth value). Such a valuation is normal iff classically correct for each connective. Carnap knew that there were non-normal snt valuations of PC, and that the gap they revealed between syntax and semantics could be "jumped" as follows. Let $VAL_{snt}$ be the set of snt valuations, and $VAL_{nrm}$ be the set of normal ones. The bottom row in the table for the wedge 'v' is not semantically determined by $VAL_{snt}$ , but if one deletes from $VAL_{snt}$ all those valuations that are not classically correct at the aforementioned row, one jumps straights to $VAL_{nrm}$ and thus to classical semantics. The conjecture we call semantic holism claims that the same thing happens for any semantic indeterminacy in any row in the table of any connective of PC, i.e., to remove it is to jump straight to classical semantics. We show (i) why semantic holism is plausible and (ii) why it is nevertheless false. And (iii) we pose a series of questions concerning the number of possible steps or jumps between the indeterminate semantics given by $VAL_{snt}$ and classical semantics given by $VAL_{nrm}$.

To most laypersons and scientists, science and progress appear to go hand in hand, yet philosophers and historians of science have long questioned the inevitability of this pairing. As we take leave of a century acclaimed for scientific advances and progress, Science at Century's End, the eighth volume of the Pittsburgh-Konstanz Series in the Philosophy and History of Science, takes the reader to the heart of this important matter. Subtitled Philosophical Questions on the Progress and Limits of Science, this timely volume contains twenty penetrating essays by prominent philosophers and historians who explore and debate the limits of scientific inquiry and their presumed consequences for science in the 21st century.

Semantic Holism is the claim that any semantic path from inferential semantics (the indeterminate semantics forced by the classical inference rules of PC) reaches all the way to classical semantics if it is even one step long. In our joint paper Semantic Holism, Belnap and I showed that some such semantic paths are two steps long, but we left open a number of questions about the lengths of semantic paths. Here I answer the most important of these questions by showing that there are infinitely long semantic paths that begin at inferential semantics but that do not even reach classical semantics. I do this by showing how to construct such an infinite semantic path from the members of the family of (n–1)-out-of-n-disjunction connectives.

Much of Grünbaum's work may be regarded as a careful development and systematic elaboration of the Riemann-Poincaré thesis of the conventionality of congruence, the thesis that the continuous manifolds of space, time, and space-time are intrinsically metrically amorphous, i.e. are devoid of intrinsic metrics. Therefore, to appreciate Grünbaum's philosophical contributions, one must have a clear understanding of what he means by an intrinsic metric. The second and fourth sections of this paper are exegetical; in them we try to piece together, from his sundry remarks about intrinsic metrics, what Grünbaum means by the term 'intrinsic metric.' We shall argue that, the customary carefulness and precision of Grünbaum's writings notwithstanding, there are residual unclarities and difficulties which beset his conception of an intrinsic metric. In the fifth section we shall propose an explication of Grünbaum's notion of an intrinsic metric which seems on the whole faithful to Grünbaum's intuitions and insights and which also seems capable of performing the philosophical services which his work demands of that notion. The third section is a digression on Zeno's metrical paradox of extension

When they abandoned the analytic-synthetic distinction, analytic philosophers substituted for it uncritical appeals to thought experiments or conceivability arguments. Although the history of philosophy is replete with thought experiments, medieval and early modern philosophers developed sophisticated theories concerning what governs what happens in thought experiments. By contrast, contemporary philosophers subscribe to the thesis of facile conception according to which casual allegations of conceivability or inconceivability are taken as good evidence of possibility or impossibility. Philosophers need to adopt standards of thought experimentation like those found in science and to ground them in a general theory of conceivability.