On the functional origins of essentialism

This essay examines the proposal that psychological essentialism results from a history of natural selection acting on human representation and inference systems. It has been argued that the features that distinguish essentialist representational systems are especially well suited for representing natural kinds. If the evolved function of essentialism is to exploit the rich inductive potential of such kinds, then it must be subserved by cognitive mechanisms that carry out at least three distinct functions: identifying these kinds in the environment, constructing essentialized representations of them, and constraining inductive inferences about kinds. Moreover, there are different kinds of kinds, ranging from nonliving substances to biological taxa to within-species kinds such as sex, and the causal processes that render these categories coherent for the purposes of inductive generalization vary. If the evolved function of essentialism is to support inductive generalization under ignorance of true causes, and if kinds of kinds vary in the implicit assumptions that support valid inductive inferences about them, then we expect different, functionally incompatible modes of essentialist thinking for different kinds. In particular, there should be differences in how biological and nonbiological substances, biological taxa, and biological and social role kinds are essentialized. The functional differences between these kinds of essentialism are discussed

Feynman loops and three-dimensional quantum gravity

This paper explores the idea that within the framework of three-dimensional quantum gravity one can extend the notion of Feynman diagram to include the coupling of the particles in the diagram with quantum gravity. The paper concentrates on the non-trivial part of the gravitational response, which is to the large momenta propagating around a closed loop. By taking a limiting case one can give a simple geometric description of this gravitational response. This is calculated in detail for the example of a closed Feynman loop in the form of a trefoil knot. The results show that when the magnitude of the momentum passes a certain threshold value, non-trivial gravitational configurations of the knot play an important role. The calculations also provide some new information about a limit of the coloured Jones polynomial which may be of independent mathematical interest.Comment: approx 14 pages. v2: minor descriptive changes and added refs. v3: minor correction

Gillraker analysis and speciation in the thread herring genus Opisthonema

ENGLISH: The thread herrings, genus Opisthonema, family Clupeidae, are marine fishes that occur only in tropical and subtropical waters off both coasts of the American continent. The genus is composed of one Atlantic species and four Pacific species. Opisthonema oglinum (LeSueur), the single species in the western Atlantic Ocean, occurs from Brazil to Massachusetts, at Bermuda, and throughout the West Indies. Opisthonema libertate (Günther), Opisthonema bulleri (Regan), and Opisthonema medirastre, new species, are Pacific coastal species which occur together from Peru to Mexico (with at least one occasionally in California). Opisthonema berlangai, new species, is confined to the vicinity of the Galapagos Islands. SPANISH: Los arenques de hebra, género Opisthonema, familia Clupeidae, son peces marinos que se encuentran sólo en aguas tropicales y subtropicales cerca a ambas costas del continente americano. El género está compuesto de una especie en el Atlántico y de cuatro en el Pacifico. Opisthonema oglinum (LeSueur), única especie que medra el Océano Atlántico occidental, se encuentra del Brasil a Massachusetts, en Bermuda, y las Indias Occidentales. Opisthonema libertate (Günther), Opisthonema bulleri (Regan), y Opisthonema medirastre, especie nueva, son especies costaneras del Pacífico que aparecen entremezcladas del Perú a México (ocasionalmente por lo menos una de ellas en California). Opisthonema berlangai, especie nueva, está confinada a la vecindad de las Islas Galápagos

Understanding death as the cessation of intentional action: A cross-cultural developmental study

Determining whether or not an entity is capable of acting intentionally is a fundamental cognitive skill that emerges in the first year of infancy, and the inability to act is a key aspect distinguishing dead from living things. Though young children’s understanding of death is generally thought to be poor, an understanding of death as the permanent cessation of agency might develop early in childhood. This study tested the cessation-of-agency hypothesis cross-culturally, by examining the differences between children’s judgments about sleeping and dead animals. The results showed that children understand that death entails the permanent cessation of the ability to act by age 4 in two different cultures. This is consistent with a view that those distinctions that are most crucial for adaptive decision-making are the ones that develop earliest

Optimization of microwave radiometric systems for earth resource surveys Final report

Optimization of passive microwave radiometric systems for earth resource surveys from ground and aircraft based measurement