A distinction should be made between the formation of stimulus-driven associations and cognitive concepts. To test the learning mode of a neural network, we propose a simple and classic input-output test: the discrimination shift task. Feed-forward PDP models appear to form stimulus-driven associations. A Hopfield network should be extended to apply the test.

Bifurcation analysis of a real-time implementation of an ART network, which is functionally similar to the generalized localist model discussed in Page's manifesto shows that it yields a phase transition from local to distributed representation owing to continuous variation of the range of inhibitory connections. Hence there appears to be a qualitative dichotomy between local and distributed representations at the level of connectionistic networks conceived of as instances of nonlinear dynamical systems.

Three arguments are given to show that neural constructivism lacks an essential ingredient to explain cognitive development. Based on results in the theory of adaptive signal analysis, adaptive biological pattern information and self-organization in nonlinear systems of information processing, it is concluded that neural constructivism should be further extended to accommodate the occurrence of phase transitions generating qualitative development in the sense of Piaget.

This article addresses the ability of Parallel Distributed Processing (PDP) networks to generate stagewise cognitive development in accordance with Piaget's theory of cognitive epigenesis. We carried out a replication study of the simulation experiments by McClelland (1989) and McClelland and Jenkins (1991) in which a PDP network learns to solve balance scale problems. In objective tests motivated from catastrophe theory, a mathematical theory of transitions in epigenetical systems, no evidence for stage transitions in network performance was found. It is concluded (...) that PDP networks lack the ability to recover the positive outcomes of analogous catastrophe analyses of real cognitive developmental data. In an attempt to further characterize the learning behaviour of PDP networks, we carried out a second simulation study using the discrimination‐shift paradigm. The results thus obtained indicate that PDP learning is compatible with the learning of stimulus‐response relationships, not with the acquisition of mediating rules such as conceived in (neo‐)Piagetian theory. In closing, we speculate about the feasibility of simulating stagewise development with alternative network architectures. (shrink)

This article addresses the ability of Parallel Distributed Processing (PDP) networks to generate stagewise cognitive development in accordance with Piaget's theory of cognitive epigenesis. We carried out a replication study of the simulation experiments by McClelland (1989) and McClelland and Jenkins (1991) in which a PDP network learns to solve balance scale problems. In objective tests motivated from catastrophe theory, a mathematical theory of transitions in epigenetical systems, no evidence for stage transitions in network performance was found. It is concluded (...) that PDP networks lack the ability to recover the positive outcomes of analogous catastrophe analyses of real cognitive developmental data. In an attempt to further characterize the learning behaviour of PDP networks, we carried out a second simulation study using the discrimination‐shift paradigm. The results thus obtained indicate that PDP learning is compatible with the learning of stimulus‐response relationships, not with the acquisition of mediating rules such as conceived in (neo‐)Piagetian theory. In closing, we speculate about the feasibility of simulating stagewise development with alternative network architectures. (shrink)

We develop and use mathematical models that describe changes in the South African population over the last decades, brought on by HIV and AIDS. We do not model all the phases in HIV progression but rather, we show that a relatively simple model is sufficient to represent the data and allows us to investigate important aspects of HIV infection: firstly, we are able to investigate the effect of awareness on the prevalence of HIV and secondly, it enables us to make (...) a comparison between South Africa and Botswana. A comparison is made between two models: a model that does not reflect awareness of the devastating impact of HIV and AIDS, and a model with an added psychological awareness factor. Both models are fitted to data that reflects the incidence of HIV and AIDS within South Africa. This allows us to examine the impact of psychological awareness. We show that inclusion of the effect of awareness is absolutely necessary to arrive at a model description that satisfactorily fits the available HIV and AIDS data for South Africa. We also show that a relatively simple modelling of awareness (as opposed to more complex mathematical techniques that have been used in past studies) is sufficient to accurately describe the observed patterns in the data. Even though awareness alone is not sufficient to eradicate any disease and other control strategies should be explored and implemented concurrently with educational campaigns, we are able to conclude (through thorough model analyses procedures) that the current level of awareness in South Africa is far below the level that is effectively required to eradicate HIV from the South African population. The awareness model is also fitted to HIV-related data for Botswana and we compare the results with the South African case. Though the effect of awareness is currently estimated at a much higher level in Botswana, other factors such as poorer health care and cultural differences may play a role in limiting the ability of awareness to combat HIV in Botswana. (shrink)

Psychiatric diagnostic covariation suggests that the underlying structure of psychopathology is not one of circumscribed disorders. Quantitative modeling of individual differences in diagnostic patterns has uncovered several broad domains of mental disorder liability, of which the Internalizing and Externalizing spectra have garnered the greatest support. These dimensions have generally been estimated from lifetime or past-year comorbidity patters, which are distal from the covariation of symptoms and maladaptive behavior that ebb and flow in daily life. In this study, structural models are (...) applied to daily diary data ( Median = 94 days) of maladaptive behaviors collected from a sample ( N = 101) of individuals diagnosed with personality disorders (PDs). Using multilevel and unified structural equation modeling, between-person, within-person, and person-specific structures were estimated from 16 behaviors that are encompassed by the Internalizing and Externalizing spectra. At the between-person level (i.e., individual differences in average endorsement across days) we found support for a two-factor Internalizing–Externalizing model, which exhibits significant associations with corresponding diagnostic spectra. At the within-person level (i.e., dynamic covariation among daily behavior pooled across individuals) we found support for a more differentiated, four-factor, Negative Affect-Detachment-Hostility-Disinhibition structure. Finally, we demonstrate that the person-specific structures of associations between these four domains are highly idiosyncratic. (shrink)

The basic reproduction ratio, R0, is a fundamental concept in epidemiology. It is defined as the total number of secondary infections brought on by a single primary infection, in a totally susceptible population. The value of R0 indicates whether a starting epidemic reaches a considerable part of the population and causes a lot of damage, or whether it remains restricted to a relatively small number of individuals. To calculate R0 one has to evaluate an integral that ranges over the duration (...) of the infection of the host. This duration is, of course, limited by remaining host longevity. So, R0 depends on remaining host longevity and in this paper we show that for long-lived hosts this aspect may not be ignored for long-lasting infections. We investigate in particular how this epidemiological measure of pathogen fitness depends on host longevity. For our analyses we adopt and combine a generic within- and between-host model from the literature. To find the optimal strategy for a pathogen from an evolutionary point of view, we focus on the indicator $$R_0^{{opt}}$$, i.e., the optimum of R0 as a function of its replication and mutation rates. These are the within-host parameters that the pathogen has at its disposal to optimize its strategy. We show that $$R_0^{{opt}}$$ is highly influenced by remaining host longevity in combination with the contact rate between hosts in a susceptible population. In addition, these two parameters determine whether a killer-like or a milker-like strategy is optimal for a given pathogen. In the killer-like strategy the pathogen has a high rate of reproduction within the host in a short time span causing a relatively short disease, whereas in the milker-like strategy the pathogen multiplies relatively slowly, producing a continuous small amount of offspring over time with a small effect on host health. The present research allows for the determination of a bifurcation line in the plane of host longevity versus contact rate that forms the boundary between the milker-like and killer-like regions. This plot shows that for short remaining host longevities the killer-like strategy is optimal, whereas for very long remaining host longevities the milker-like strategy is advantageous. For in-between values of host longevity, the contact rate determines which of both strategies is optimal. (shrink)

J. L. Ackrill's work on Plato and Aristotle has had a considerable influence upon ancient philosophical studies in the late twentieth century. In his writings the rigour and clarity of contemporary analytic philosophy are brought to bear upon ancient thought; in many cases he has provided thefirst analytic treatment of a key issue. Gathered now in this volume are the best of Ackrill's essays on the two greatest philosophers of antiquity. With philosophical acuity and philological expertise he examines a wide (...) range of texts and topics--from ethics and logic to epistemology andmetaphysics--which continue to be in the focus of debate. (shrink)

According to the legend, Bishop Wilberforce at a meeting of the British Association for the Advancement of Science in Oxford on Saturday, June 30th, 1860, turned to Thomas Huxley, and asked him ``Is it on your grandfather's or your grandmother's side that you claim descent from a monkey''; whereupon Huxley delivered a devastating rebuke, thereby establishing the primacy of scientific truth over ecclesiastical obscurantism. Although the legend is historically untrue in almost every detail, its persistence suggests that it may nonetheless (...) be true in some deeper, mythical, sense. To explore this possibility the British Academy has invited Dr Janet Browne to be a neo-Huxley confronting Mr J.R. Lucas, as a neo-Wilberforce, with each reconsidering their earlier arguments. (shrink)

The study of post-Aristotelian philosophy is constantly confused by the perplexing way in which the names of philosophers recur. Zeno, the founder of Stoicism, is sufficiently well known not be confused with either Zeno the Eleatic or the later Stoic, Zeno of Tarsus, a disciple of Chrysippus; but when we come to less distinguished names the opportunity of error is greater. If two philosophers of the same name are prominent members of different schools, there ought to be no obscurity, but (...) in an age of eclecticism one school will sometimes adopt doctrines from another, and so make classification difficult. (shrink)

No tragic poet uses the phrase μxs22EFνος πνxs22EFουσαν, except Aeschylus, who employs it in describing the Erinyes, not a Greek maiden. Similarly Homer of his ‘Mut-schnaubende’ heroes and of the savage steeds of Diomed. Hence, in the Sophoclean passage, some scribe may have mistaken the familiar ΜΕΝΟCΠΝΕΟΤCΑΝ for the more unusual ΜΕΝΕΙCΙCΤΝΟΤCΑΝ. Initial C attached itself to the preceding word, and ΤΝΟΤCΑΝ became ΠΝΟΤCΑΝ, which was promptly changed to πνxs22EFουσαν.

B erkeley wrote of ‘the absolute existence of unthinking things’ as being, ‘words which are without meaning and including a contradiction’. There are few philosophers today who do not regard Berkeley as having been mistaken in this view, in that it is regarded as clearly not meaningless to suppose that there might be many objects about which no one happens to be thinking. Nor is it the aim of this paper entirely to resurrect such a view, though it is my (...) purpose to try to show the subtlety of the logical and ontological issues involved in the problem of independent things. (shrink)

“Multiculturalism”, “pluralism” and “tolerance” have become buzz words in applied ethics. While serious and well thought out work is going on in these areas, a misunderstanding of the importance of tolerance, and the difficulties raised by multicultural moral conflict seems common. In this paper I argue that intolerance of some cultural traditions is morally required, and suggest that the forging of a moral mono-culture is preferable to pluralism.

The statement, that these or those philosophers do not accept the distinction between what is, and what is not, ?given? in perception, has very little content; and should receive only a corresponding degree of emphasis.

Barrett finds lines 1010–15 difficult. He says that ‘hovers between “an heiress as my wife” and “marriage with an heiress”’, that ‘a Greek heiress did not inherit property as her own: it passed not to her but with her, to her husband and ultimately to her children.—In Attic law a widow was never : a man's property went to his legitimate children.

The object of this article is to discuss, defend, and supplement the only definite piece of evidence we possess which deals with the musical scalesreferred to by Plato in the Republic . In this first section I shall consider the list of scales given by Aristides Quintilianus and suggest the source from which it is derived; in the second part the employment of certain abnormal intervals will be established and elucidated; and finally the evidence of the preceding sections will be (...) reviewed from the standpoint of the Pythagorean musical theory. (shrink)

The Dative or Ablative of this ‘plurale tantum’ was used by one of the earlier Republican writers. It is quoted by Ps.-Placidus from a MS. which had the marginal note ‘capillis muliebribus ante, id est a fronte, pendentibus.’ These marginal notes were often direct traditions from the earliest glossographi, the ‘glossematum scriptores,’ who provided material also for Varro and Verrius Flaccus, either directly or through the writings of earlier grammatici.

A number of Democritean fragments may loosely be called ‘political’, concerned as they are with questions to do with the πλις – with government, with the duties and dangers of public office, with justice, law and order. The majority of them have been preserved in chapters of Stobaeus’ anthology entitled ‘On the State’ , ‘On Laws and Customs’ , ‘On Government’.

The achievements of the textile industry in Roman Britain are often underestimated as a result of the meagreness of our available evidence. The Edict on maximum prices issued by Diocletian in A.D. 301 shows that British capes commanded high prices on the markets of the Empire, and that in the late third century A.D. British rugs were the best in the world. In view of the competition from the traditional centres of rug manufacture in the East, this is an astonishing (...) achievement. (shrink)

In this, his last work, J. David Greenstone provides an important new analysis of American liberalism and of Lincoln's unique contribution to the nation's political life. Greenstone addresses Louis Hartz's well-known claim that a tradition of liberal consensus has characterized American political life from the time of the founders. Although he acknowledges the force of Hartz's thesis, Greenstone nevertheless finds it inadequate for explaining prominent instances of American political discord, most notably the Civil War. Originally published in 1993. The Princeton (...) Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905. (shrink)

The term Volkskerk in the Church Order of the Nederduitsch Hervormde Kerk van AfrikaThe Nederduitsch Hervormde Kerk states in its Church Order that it is a volkskerk. In this article the term volkskerk and the historical line of how it came to use in the Nederduitsch Hervormde Kerk, is researched. In the light of these statements the term volkskerk and its meaning in the contemporary Order of the Nederduitsch Hervormde Kerk, is dealt with.