1. Introduction. In (Kripke 1970), Saul Kripke distinguished rigid from accidental designators to refute the Frege-Russell theory of names, to rehabilitate natural necessity, and to subvert mind-body dualism. Discussions of Kripke's work have tended to follow this agenda. Here I examine a possible extension of Kripke's apparatus to scientific reduction and physical necessity. My overall conclusions are negative: while Kripkean arguments appear to yield surprising conclusions that cut against empiricism, these conclusions merely restate empiricist tenets in mildly paradoxical terms. The larger moral is that contemporary essentialism is less philosophically significant that has perhaps been supposed.

A solution of the Zeno paradoxes in terms of a discrete space is usually rejected on the basis of an argument formulated by Hermann Weyl, the so-called tile argument. This note shows that, given a set of reasonable assumptions for a discrete geometry, the Weyl argument does not apply. The crucial step is to stress the importance of the nonzero width of a line. The Pythagorean theorem is shown to hold for arbitrary right triangles.

Foss's critique of van Fraassen's constructive empiricism is shown to be completely wide of the mark (Foss 1984, van Fraassen 1980). Foss misunderstands van Fraassen's use of the terms ‘observable’, ‘phenomena’, ‘empirical adequacy’, and ‘epistemic community’. He misconstrues constructive empiricism as making knowledge, and perhaps existence, dependent on the observer. On the basis of this error, he attempts to reduce constructive empiricism to skepticism. None of his criticisms are to the point.