2000 HSS/PSA Program 1 - History of Science Society

PSA Abstracts
beliefs. The analogous nature of perceptual symbols and the spatial nature of
intraconceptual relations impose new constraints to attribute selection. These
constraints help people with different background beliefs select compatible
attributes, which constitute a common “platform” for taxonomy comparison.
Wayne Christensen University of Newcastle
C.␣ A. Hooker University of Newcastle
Self-directed anticipative learning processes in science
A major problem facing current philosophy of science is how to integrate
accounts of individual cognition and social processes into a cognitive theory
of science. However an interactivist-constructivist (I-C) approach to cognition
based in organised processes casts light on these problems by highlighting the
role of interaction in the construction and modification of scientific research.
This paper develops some of the implications of I-C for understanding the
scientific process by extending to science an original, naturally situated
cognitive learning model, self-directed anticipative learning.
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Rob Clifton University of Pittsburgh
Nonlocality and Entanglement in Quantum Information Theory
It is a widely held belief that the key to quantum enhancements of classical
computation power lies in the availability of entangled states. And one can
hardly doubt that entanglement and/or non-locality is an important resource
in quantum information processing, as illustrated by quantum teleportation
and dense coding. It is not surprising, then, that physicists in recent years have
been led to a far deeper understanding of the nature of entanglement. The
central foundational problems that remain involve characterizing, in the case
of a mixed quantum state (representable only by a density operator) “how
entangled” the state is and “how nonlocal” it is. For example, while there is a
uniquely natural measure of entanglement for pure states, based on von
Neumann entropy, there are a number of apparently distinct yet useful measures
for mixed entangled states. Moreover, there are mixed entangled states that
are ‘bound entangled’, i.e., no pure entanglement (in the form of singlet states)
can be distilled from them. At a more fundamental level, while every pure
entangled state dictates nonlocal Bell correlations (violates some Bell
inequality), mixed entangled states need not; yet, perhaps strangely, such “Bell
insensitive” states can still be used to teleport with a delity better than any
possible classical implementation! Bell-correlated states must necessarily be
entangled. However, there is no known characterization of the Bell-correlated
mixed states amongst those that are entangled, beyond the simplest case of a