Essence of Concern

Presidential Address of Dr. J. E. Holoubek to the Executive Board dele1gates attending the annual meeting in Atlantic City, New Jersey, June 16, 196

Cosmological k-essence condensation

We consider a model of dark energy/matter unification based on a k-essence type of theory similar to tachyon condensate models. Using an extension of the general relativistic spherical model which incorporates the effects of both pressure and the acoustic horizon we show that an initially perturbative k-essence fluid evolves into a mixed system containing cold dark matter like gravitational condensate in significant quantities.Comment: 8 pages, 2 figures, presented by NB at the conference Beyond 2010, Cape Town, 1-6 February 201

The Essence of Inheritance

Programming languages serve a dual purpose: to communicate programs to computers, and to communicate programs to humans. Indeed, it is this dual purpose that makes programming language design a constrained and challenging problem. Inheritance is an essential aspect of that second purpose: it is a tool to improve communication. Humans understand new concepts most readily by first looking at a number of concrete examples, and later abstracting over those examples. The essence of inheritance is that it mirrors this process: it provides a formal mechanism for moving from the concrete to the abstract.Comment: This paper was submitted for inclusion in a Festschrift entitled "A list of successes that can change the world", to be published by Springe

Quintessence as k-essence

Quintessence and k-essence have been proposed as candidates for the dark energy component of the universe that would be responsible of the currently observed accelerated expansion. In this paper we investigate the degree of resemblance between those two theoretical setups, and find that every quintessence model can be viewed as a k-essence model generated by a kinetic linear function. In addition, we show the true effects of k-essence begin at second order in the expansion of the kinetic function in powers of the kinetic energy.Comment: 14 pages, improved discussion, matches published versio

The Essence of Hemlocks

Poetry by Haley Huelsman

Aristotle on Essence and Habitat

Despite his awareness that organisms are well suited to the habitats they are typically found in, Aristotle nowhere tries to explain this. It is unlikely that he thinks this “fit” (as I call it) between organisms and their habitats is simply a lucky coincidence, given how vehemently he rejects that as an explanation of the fit between organisms’ various body parts. But it is quite puzzling that Aristotle never explicitly addresses this, since it is a question that seemed so pressing to later philosophers and biologists such as Darwin. In this paper I offer a solution to that puzzle. As I argue, the type of habitat an organism lives in is partly constitutive of its essence or nature. The reason Aristotle does not ask, for instance, why marsh-dweller birds live in marshes, is that it is simply constitutive of their nature that they do so. Given that habitat is built into a kind’s essence, the answer to such a question is obvious and the question would have seemed to him trivial. By attending to the details of his biological treatises, I show that Aristotle’s conception of a living being’s essence is much more nuanced than one can glean from his discussions in the Physics and Metaphysics alone