Summary The common view has been that Darwin regarded species as artificial and arbitrary constructions of taxonomists, not as distinct natural units. However, in his transmutation notebooks he clearly subscribed to the reality of species, on the basis of the criterion of non-interbreeding. A consequence of this biological species concept was his identification of the acquisition of reproductive isolation as the mark of the completion of speciation. He developed in the notebooks a theory of geographic speciation on the grounds of (...) (a) an empirical correlation between barriers and the geographical distributions of allied species, (b) the analogy of artificial isolation in the formation of new domesticated varieties, and (c) the logical consequence of blending inheritance. A brief discussion of Darwin's species concept in later writings concludes the paper. (shrink)

Hugo de Vries claimed that he had discovered Mendel's laws before he found Mendel's paper. De Vries's first ratios, published in 1897, for the second generation of hybrids were 2/3:1/3 and 80%:20%. By 1900, both of these ratios had become 3:1. These changing ratios suggest that as late as 1897 de Vries had not discovered the laws, although he asserted, from 1900 on, that he had found the laws in 1896. An Appendix details de Vries's Mendelian experiments as described in (...) the original edition of volume two of Die Mutationstheorie, but omitted entirely from the English translation. (shrink)

This book traces the intellectual revolution initiated by Thales in the sixth century BC to its culmination in the metaphysics of Parmenides.

In lieu of an abstract, here is a brief excerpt of the content:Comments on “Moral Complicity in Induced Pluripotent Stem Cell Research”W. Malcolm Byrnes, Ph.D. and Edward J. FurtonIn his article titled “Moral Complicity in Induced Pluripotent Stem Cell Research,” Mark T. Brown (2009) unfortunately mischaracterizes my ethical analysis of the use of induced pluripotent stem (iPS) cells for replacement therapies, or treatments (Byrnes 2008). In my paper, which Brown cites, I argue that, just as it is ethically acceptable (...) for parents to allow their children and themselves to be immunized using vaccines produced by cell lines derived from human fetuses aborted in the past, it is also acceptable for persons in the future to benefit from treatments that use iPS cells validated using human embryonic stem (ES) cell lines [End Page 202] derived in the past. The assumption I make is that iPS cells would have to be shown to be functionally equivalent to human ES cells—i.e., validated—before they could be used for cell replacement treatments. (If it turns out that this assumption is incorrect, and primate or even mouse ES cells can be used for the validation, then all residual ethical problems will disappear and there will be no ethical problems whatsoever associated with iPS cells.) I wrote:... [I]n both cases, the origin of the treatment is in a one-time event: either the one-time use of aborted fetuses to obtain cell lines (e.g., MRC-5 and WI- 38) to grow weakened virus strains for vaccine production, or the one-time destruction of human embryos to validate iPS cells, which then effectively replace embryonic stem cells. In the latter case, if no additional embryonic stem cell lines are derived, then derivation of the existing lines could be considered a “one-time” event in the past, albeit an event that extended over a several-year period(Byrnes 2008, p. 287, emphasis added).Note the phrase “if no additional embryonic stem cell lines are derived.” The derivation of ES cell lines inherently involves destruction of embryos; indeed, that is why many people, including me, are opposed to human ES cell research. In my article, I am arguing that, if no additional ES cell lines are derived, then no additional human embryos will be destroyed, and the destruction of human embryos will lie in the past. In this case, embryo destruction could be considered a past event, just as the abortion of a human fetus from which vaccine-producing cell lines were derived is a past, albeit tragic, event.In the process of building his argument that proponents of iPS cell research are morally complicit in embryo destruction, Brown (2009, p. 15) casts me as being in favor of the “derivation of new embryonic stem [cell lines].” This is the exact opposite of my position. In fact, I am opposed to further destruction of human embryos. I believe that the hundreds of ES cell lines already in existence are more than sufficient to validate iPS cells and so no additional lines need to be derived. This means that no additional human embryos will need to be destroyed.Apparently based on the misperception that I support future destruction of human embryos, Brown concludes that “Byrnes’s endorsement of ongoing iPSC validation studies would seem to implicate him and those who follow his lead in formal and material complicity in what they perceive as moral evil” (p. 16). He writes that “explicit formal complicity would attach because he [Byrnes] knowingly and intentionally recommends that embryos be killed in order to facilitate a transition to a future in which no more embryos need be destroyed” (p. 16). Additionally, my “followers” and I would be guilty of “proximate material complicity” as well as “remote material complicity” (p. 16). Unfortunately, this broad condemnation is based on a misconception of my actual position.An additional problem involves Brown’s use of a quotation he attributes to me: [End Page 203]Once embryonic stem cells are used to successfully validate iPS cells, they will no longer be needed and their association with iPS cells will lie in the past. Is there not an element of sadness and resignation in accepting something (iPS cells) associated with an unjust act (destruction of an... (shrink)

In 1962 I offered an analysis of the Line and Cave which maintained that the four main divisions of each are parallel and interpreted the three stages of ascent in the Cave allegory as representing the three stages in Plato's educational programme: music and gymnastic, mathematics and dialectic. At that time a major portion of my task was to counter arguments which purported to show that the Line and Cave could not be parallel. The present situation is quite different since (...) recent writers, for the most part, not only take the four main divisions of the Cave as parallel to those of the Line, but also accept the restriction of the Cave allegory to moral and mathematical education as a crucial step in the establishing of this fact. This last move, which is clearly in harmony with the form and content of the Republic, enables us to allow for the ordinary unenlightened man to be at the bottom level of the Cave without our having to suggest that he confuses the shadows of visual objects with their originals, which could well be the case if the Cave were taken to represent all sense perception as such. Despite fairly general agreement on these basic points of interpretation there remains, however, a wide divergence of opinion as to the significance of the various levels of education or moral awareness portrayed by the Cave. In keeping with several recent papers on this topic I shall focus my attention on the bottom two stages of this allegory: the state of the prisoners viewing shadows on the cave wall and that of the released prisoners, still in the cave, but turned around and looking at the puppets which cast these shadows. (shrink)

Family carers of individual’s living with Huntington’s Disease (HD) manage a distinct and unique series of difficulties arising from the complex nature of HD. This paper presents the validation of the definitive measure of quality of life for this group. The Huntington’s Disease Quality of Life Battery for carers (HDQoL-C) was expanded and then administered to an international sample of 1716 partners and family carers from 13 countries. In terms of the psychometric properties of the tool, exploratory analysis of half (...) of the sample, demonstrated good internal consistency and reliability. Some items on the full version did not meet psychometric thresholds and a short version (HDQoL-Cs) was developed based on more stringent criteria. Confirmatory Factor Analysis of the model structure showed a good fit for all Factors and, indicated that the HDQoL-C and HDQoL-Cs are psychometrically robust measures of quality of life. We found that carers who lived with and looked after their spouse/partner had reduced sense of coping, hope for the future and overall quality of life. Carers with children who were at risk, carried the gene or were symptomatic also had poorer quality of life outcomes. Findings indicated the HDQoL-C and HDQoL-Cs are valid in multiple languages and across varied cultures as measures of self-reported quality of life in family carers of individual’s living with HD. These psychometrically validated tools can aid and guide the implementation of therapeutic interventions to improve life quality in this population. (shrink)

Despite the known positive effects of acute exercise on cognition, the effects of a competitive team sport match are unknown. In a randomized crossover design, 20 female and 17 male field hockey players completed a battery of cognitive tests prior to, at half-time, and immediately following a competitive match ; with effect sizes presented as raw ES from mixed effect models. Blood samples were collected prior to and following the match and control trial, and analyzed for adrenaline, noradrenaline, brain derived (...) neurotrophic factor, cathepsin B, and cortisol. The match improved response times for a simple perception task at full-time and response times on the complex executive function task improved at half-time. Working memory declined at full-time on the match. The change in working memory was negatively correlated with increases in cortisol, as was the change in simple perception response time and the change in noradrenaline concentration. This study is the first to highlight the effects a competitive hockey match can have on cognition. These findings have implications for performance optimization, as understanding the influence on specific cognitive domains across a match allows for the investigation into strategies to improve these aspects. (shrink)

A judgement analysis of people's social inferences of attitudes and ability was conducted. University students were asked to infer the liberalness ( N = 60; Study 1) or intelligence ( N = 40; Study 2) of targets seen in pictures. Multiple regression analyses revealed that attractiveness was the most important cue for predicting inferences of liberalness, while an ethnic cue (i.e., being Asian) was the most important cue for judgements about intelligence. Results also showed that a single-cue model was less (...) susceptible to overfitting, but significantly less accurate than a multiple-cue model in predicting participant's intelligence judgements. Although the multiple regression models suffered a degree of overfitting, cross validation showed that they continued to have significant predictive value when applied to new data. Furthermore, a “random partner” method (comparing each participant's own regression equation with that of another, randomly selected, participant) provided evidence of significant idiosyncratic variation in the way intelligence judgements were made. (shrink)

When a study shows statistically significant correlation between an exposure and an outcome, the credence of a real connection between the two increases. Should that credence remain the same when it is discovered that further independent studies between the exposure and other independent outcomes were conducted? Matthew Kotzen argues that it should remain the same, even if the results of those further studies are discovered. However, we argue that it can differ dependent upon the results of the studies.

A simple numerical procedure is presented for the problem of estimating the parameters of models for the distribution of eggs oviposited in a host. The modelling is extended to incorporate both host density and time dependence to produce a remarkably parsimonious structure with only seven parameters to describe a data set of over 3,000 observations. This is further refined using a mixed model to accommodate several large outliers. Both models show that the level of superparasitism declines with increasing host density, (...) and the rate declines over time. It is proposed that the differing behaviours represented by the mixed model may reflect a balance between behavioural strategies of different selective benefit. (shrink)

A simple numerical procedure is presented for the problem of estimating the parameters of models for the distribution of eggs oviposited in a host. The modelling is extended to incorporate both host density and time dependence to produce a remarkably parsimonious structure with only seven parameters to describe a data set of over 3,000 observations. This is further refined using a mixed model to accommodate several large outliers. Both models show that the level of superparasitism declines with increasing host density, (...) and the rate declines over time. It is proposed that the differing behaviours represented by the mixed model may reflect a balance between behavioural strategies of different selective benefit. (shrink)