MIRACLES AND TWO ACCOUNTS OF SCIENTIFIC LAWS

Since early modernity, it has often been assumed that miracles are incompatible with the existence of the natural laws utilized in the sciences. This paper argues that this assumption is largely an artifact of empiricist accounts of laws that should be rejected for reasons internal to philosophy of science, and that no such incompatibility arises on the most important alternative interpretations, which treat laws as expressions of forces, dispositions, or causal powers.     

Applying Recent Argumentation Methods to Some Ancient Examples of Plausible Reasoning

Plausible (eikotic) reasoning known from ancient Greek (late Academic) skeptical philosophy is shown to be a clear notion that can be analyzed by argumentation methods, and that is important for argumentation studies. It is shown how there is a continuous thread running from the Sophists to the skeptical philosopher Carneades, through remarks of Locke and Bentham on the subject, to recent research in artificial intelligence. Eleven characteristics of plausible reasoning are specified by analyzing key examples of it recognized as important in ancient Greek skeptical philosophy using an artificial intelligence model called the Carneades Argumentation System (CAS). By applying CAS to ancient examples it is shown how plausible reasoning is especially useful for gaining a better understanding of evidential reasoning in law, and argued that it can also be applied to everyday argumentation. Our analysis of the snake and rope example of Carneades is also used to point out some ways CAS needs to be extended if it is to more fully model the views of this ancient philosopher on argumentation.     

Common and specific cognitive deficits in schizophrenia: relationships to function

The goals of the present study were to assess the interrelationships among tasks from the MATRICS and CNTRACS batteries, to determine the degree to which tasks from each battery capture unique variance in cognitive dysfunction in schizophrenia, and to determine the ability of tasks from each battery to predict functional outcome. Subjects were 104 schizophrenia patients and 132 healthy control subjects recruited as part of the CNTRACS initiative. All subjects completed four CNTRACS tasks and two tasks from the MATRICS battery: Brief Assessment of Cognition in Schizophrenia Symbol Coding and the Hopkins Verbal Learning Test. Functional outcome was also assessed in the schizophrenia subjects. In both the patient and control groups, we found significant intercorrelations between all higher order cognitive tasks (episodic memory, goal maintenance, processing speed, verbal learning) but minimal relationships with the visual task. For almost all tasks, scores were significantly related to measures of functional outcome, with higher associations between CNTRACS tasks and performance-based measures of function and between one of the MATRICS tasks and self-reported functioning, relative to the other functioning measures. After regressing out variance shared by other tasks, we continued to observe group differences in performance among task residuals, particularly for measures of episodic memory from both batteries, although these residuals did not correlate as robustly with functional outcome as raw test scores. These findings suggest that there exists both shared and specific variance across cognitive tasks related to cognitive and functional impairments in schizophrenia and that measures derived from cognitive neuroscience can predict functional capacity and status in schizophrenia.     

Persistent and stable biases in spatial learning mechanisms predict navigational style

A wealth of evidence in rodents and humans supports the central roles of two learning systems—hippocampal place learning and striatal response learning—in the formation of spatial representations to support navigation. Individual differences in the ways that these mechanisms are engaged during initial encoding and subsequent navigation may provide a powerful framework for explaining the wide range of variability found in the strategies and solutions that make up human navigational styles. Previous work has revealed that activation in the hippocampal and striatal networks during learning could predict navigational style. Here, we used functional magnetic resonance imaging to investigate the relative activations in these systems during both initial encoding and the act of dynamic navigation in a learned environment. Participants learned a virtual environment and were tested on subsequent navigation to targets within the environment. We observed that a given individual had a consistent balance of memory system engagement across both initial encoding and subsequent navigation, a balance that successfully predicted the participants’ tendencies to use novel shortcuts versus familiar paths during dynamic navigation. This was further supported by the observation that the activation during subsequent retrieval was not dependent on the type of solution used on a given trial. Taken together, our results suggest a model in which the place- and response-learning systems are present in parallel to support a variety of navigational behaviors, but stable biases in the engagement of these systems influence what solutions might be available for any given individual.     

Word skipping during sentence reading: effects of lexicality on parafoveal processing

Two experiments examined how lexical status affects the targeting of saccades during reading by using the boundary technique to vary independently the content of a letter string when seen in parafoveal preview and when directly fixated. Experiment 1 measured the skipping rate for a target word embedded in a sentence under three parafoveal preview conditions: full preview (e.g., brain–brain), pseudohomophone preview (e.g., brane–brain), and orthographic nonword control preview (e.g., brant–brain); in the first condition, the preview string was always an English word, while in the second and third conditions, it was always a nonword. Experiment 2 investigated three conditions where the preview string was always a word: full preview (e.g., beach–beach), homophone preview (e.g., beech–beach), and orthographic control preview (e.g., bench–beach). None of the letter string manipulations used to create the preview conditions in the experiments disrupted sublexical orthographic or phonological patterns. In Experiment 1, higher skipping rates were observed for the full (lexical) preview condition, which consisted of a word, than for the nonword preview conditions (pseudohomophone and orthographic control). In contrast, Experiment 2 showed no difference in skipping rates across the three types of lexical preview conditions (full, homophone, and orthographic control), although preview type did influence reading times. This pattern indicates that skipping not only depends on the presence of disrupted sublexical patterns of orthography or phonology, but also is critically dependent on processes that are sensitive to the lexical status of letter strings in the parafovea.     

Condom Use Among South African University Students in the Province of KwaZulu-Natal

South Africa has one of the highest HIV infection rates in the world, with young people particularly affected. Condoms are an effective preventative method against HIV among sexually active adults. This study assessed the level of condom usage among university students in South Africa and their attitudes towards condom usage, negotiation efficacy and confidence in condom usage. It was a cross-sectional study conducted amongst South African university students living at the university residences. Students were randomly selected and required to complete a self-administered questionnaire. The mean age of participants (n?=?441) was 22.7?±?4.3 years. The mean age of sexual debut was 17.7?±?3.0 years with 1.4?±?1.47 (range 0–13) current partners. Less than half of the students used a condom at sexual debut and only 28.5% used condoms during recent sexual activity. Those students who used a condom at first sexual intercourse had marginally more positive attitudes about condom usage than those who did not do so (p?=?0.056). Students with a single current partner had more positive attitudes about condom usage than those with multiple current partners (p?=?0.021). Only 32.5% (n?=?127) of the students were very confident in using condoms. Similarly, only 33.0% (n?=?130) of the participants felt that they could definitely negotiate condom use with their partners. We conclude that condom use among South African students is low and that they lack the confidence to use condoms. We recommend that programmes to step up condom use must also incorporate educational interventions on usage.