The communication of first-person thoughts

A discussion of Frege's views concerning the meaning of 'I' and his distinction between the 'I' of soliloquy and the 'I' of conversation

Ambiguous figures and the content of experience

Representationalism is the position that the phenomenal character of an experience is either identical with, or supervenes on, the content of that experience. Many representationalists hold that the relevant content of experience is nonconceptual. I propose a counterexample to this form of representationalism that arises from the phenomenon of Gestalt switching, which occurs when viewing ambiguous figures. First, I argue that one does not need to appeal to the conceptual content of experience or to judgements to account for Gestalt switching. I then argue that experiences of certain ambiguous figures are problematic because they have different phenomenal characters but that no difference in the nonconceptual content of these experiences can be identified. I consider three solutions to this problem that have been proposed by both philosophers and psychologists and conclude that none can account for all the ambiguous figures that pose the problem. I conclude that the onus is on representationalists to specify the relevant difference in content or to abandon their position

Quantifying the connectivity of a network: The network correlation function method

Networks are useful for describing systems of interacting objects, where the nodes represent the objects and the edges represent the interactions between them. The applications include chemical and metabolic systems, food webs as well as social networks. Lately, it was found that many of these networks display some common topological features, such as high clustering, small average path length (small world networks) and a power-law degree distribution (scale free networks). The topological features of a network are commonly related to the network's functionality. However, the topology alone does not account for the nature of the interactions in the network and their strength. Here we introduce a method for evaluating the correlations between pairs of nodes in the network. These correlations depend both on the topology and on the functionality of the network. A network with high connectivity displays strong correlations between its interacting nodes and thus features small-world functionality. We quantify the correlations between all pairs of nodes in the network, and express them as matrix elements in the correlation matrix. From this information one can plot the correlation function for the network and to extract the correlation length. The connectivity of a network is then defined as the ratio between this correlation length and the average path length of the network. Using this method we distinguish between a topological small world and a functional small world, where the latter is characterized by long range correlations and high connectivity. Clearly, networks which share the same topology, may have different connectivities, based on the nature and strength of their interactions. The method is demonstrated on metabolic networks, but can be readily generalized to other types of networks.Comment: 10 figure

The silence of self-knowledge

Gareth Evans famously affirmed an explanatory connection between answering the question whether p and knowing whether one believes that p. This is commonly interpreted in terms of the idea that judging that p constitutes an adequate basis for the belief that one believes that p. This paper formulates and defends an alternative, more modest interpretation, which develops from the suggestion that one can know that one believes that p in judging that p

Personal and sub-personal: a defence of Dennett's early distinction

Since 1969, when Dennett introduced a distinction between personal and sub‐personal levels of explanation, many philosophers have used ‘sub‐personal’ very loosely, and Dennett himself has abandoned a view of the personal level as genuinely autonomous. I recommend a position in which Dennett's original distinction is crucial, by arguing that the phenomenon called mental causation is on view only at the properly personal level. If one retains the commit‐’ ments incurred by Dennett's early distinction, then one has a satisfactory anti‐physicalistic, anti‐dualist philosophy of mind. It neither interferes with the projects of sub‐personal psychology, nor encourages ; instrumentalism at the personal level. People lose sight of Dennett’s personal/sub-personal distinction because they free it from its philosophical moorings. A distinction that serves a philosophical purpose is typically rooted in doctrine; it cannot be lifted out of context and continue to do its work. So I shall start from Dennett’s distinction as I read it in its original context. And when I speak of ‘the distinction’, I mean to point not only towards the terms that Dennett first used to define it but also towards the philosophical setting within which its work was cut out

Novel colours and the content of experience

I propose a counterexample to naturalistic representational theories of phenomenal character. The counterexample is generated by experiences of novel colours reported by Crane and Piantanida. I consider various replies that a representationalist might make, including whether novel colours could be possible colours of objects and whether one can account for novel colours as one would account for binary colours or colour mixtures. I argue that none of these strategies is successful and therefore that one cannot fully explain the nature of the phenomenal character of perceptual experiences using a naturalistic conception of representation

Placement, support, and retention of health professionals: national, cross-sectional findings from medical and dental community service officers in South Africa

Background: In South Africa, community service following medical training serves as a mechanism for equitable distribution of health professionals and their professional development. Community service officers are required to contribute a year towards serving in a public health facility while receiving supervision and remuneration. Although the South African community service programme has been in effect since 1998, little is known about how placement and practical support occur, or how community service may impact future retention of health professionals. Methods: National, cross-sectional data were collected from community service officers who served during 2009 using a structured self-report questionnaire. A Supervision Satisfaction Scale (SSS) was created by summing scores of five questions rated on a three-point Likert scale (orientation, clinical advising, ongoing mentorship, accessibility of clinic leadership, and handling of community service officers’ concerns). Research endpoints were guided by community service programmatic goals and analysed as dichotomous outcomes. Bivariate and multivariate logistical regressions were conducted using Stata 12. Results: The sample population comprised 685 doctors and dentists (response rate 44%). Rural placement was more likely among unmarried, male, and black practitioners. Rates of self-reported professional development were high (470 out of 539 responses; 87%). Participants with higher scores on the SSS were more likely to report professional development. Although few participants planned to continue work in rural, underserved communities (n = 171 out of 657 responses, 25%), those serving in a rural facility during the community service year had higher intentions of continuing rural work. Those reporting professional development during the community service year were twice as likely to report intentions to remain in rural, underserved communities. Conclusions: Despite challenges in equitable distribution of practitioners, participant satisfaction with the compulsory community service programme appears to be high among those who responded to a 2009 questionnaire. These data offer a starting point for designing programmes and policies that better meet the health needs of the South African population through more appropriate human resource management. An emphasis on professional development and supervision is crucial if South Africa is to build practitioner skills, equitably distribute health professionals, and retain the medical workforce in rural, underserved areas

Epidemiology of sorghum anthracnose (Colletotrichum sublineolum) and leaf blight (Exserohilum turcicum) in Kenya

A 3-year study on the epidemiology of sorghum anthracnose (Colletotrichum sublineolum) and leaf blight (Exserohilum turcicum [Setosphaeria turcica]) was conducted at Alupe in western Kenya from 1994 to 1996. A nonlinear logistic model was used to summarize 72 anthracnose and 108 leaf blight disease progress curves from different planting dates and cultivars. Effects of planting date and cultivar on disease development were compared based on estimates of the rate (β), the absolute rate (θ), inflection point (μ) and upper asymptote (γ), disease severity at milk stage (v95), and time taken to reach a disease severity of 2% (t2, an estimate of time when disease is first observed). Leaf blight epidemics always started earlier than those of anthracnose, but exhibited lower disease severity at crop maturity. Effects of planting date and cultivar on β varied between years. Delaying planting reduced time to disease onset (i.e. µ and t2) and increased absolute rate of progress θ, resulting in maximum severity at crop 'milk stage' and maturity (v95 and γ, respectively). Resistant cultivars had highest µ and t2 but lowest θ, v95 and γ values for both diseases. Delaying planting affected anthracnose progress more on the resistant cultivars, in contrast with leaf blight for which progress on susceptible cultivars was more affected. The implications of these findings for disease management are discussed, and recommendations made to improve disease screening methodologie

Planck pre-launch status: HFI beam expectations from the optical optimisation of the focal plane

Planck is a European Space Agency (ESA) satellite, launched in May 2009, which will map the cosmic microwave background anisotropies in intensity and polarisation with unprecedented detail and sensitivity. It will also provide full-sky maps of astrophysical foregrounds. An accurate knowledge of the telescope beam patterns is an essential element for a correct analysis of the acquired astrophysical data. We present a detailed description of the optical design of the High Frequency Instrument (HFI) together with some of the optical performances measured during the calibration campaigns. We report on the evolution of the knowledge of the pre-launch HFI beam patterns when coupled to ideal telescope elements, and on their significance for the HFI data analysis procedure