A response to Penrose’s “Sandel on enhancement: A response to Van Niekerk”

In this article the author responds to Brian Penrose’s critical response to his (Van Niekerk’s) article “Biomedical enhancement and the pursuit of mastery and perfection: a critique of the views of Michael Sandel” that appeared in the PSSA conference edition of the SAJP 33(2), 2014. While Van Niekerk is appreciative of the opportunity for spirited dialogue that Penrose’s response provides, he nevertheless takes issue with several charges Penrose raises. He responds to Penrose’s claims that Van Niekerk does not fully understand “the Sandel project” and thus that Van Niekerk creates and shoots down a straw man in his argument against Sandel. Van Niekerk argues that Penrose’s claims are indicative of significant methodological differences between their respective approaches. Penrose acknowledges the “fuzziness” of Sandel’s arguments with regards to biomedical enhancement. He then develops an interpretation of Sandel’s views that claims to have “filled in the complete picture” of what Sandel attempts to do, and then reproaches Van Niekerk for not responding to that “completed picture”, i.e. the “Sandel project”. Van Niekerk finds this to be an unreasonable and methodologically highly problematic demand on him. Van Niekerk responds to a number of Penrose’s arguments, and then concludes that while there are, of course, good reasons to exercise caution at the prospect of biomedical enhancement with regard to its risks, the possibilities offered by enhancement need not elicit a prima facie reaction of pessimism. Rather, such prospects can also be regarded in a positive light as an exciting opportunity to take our own evolution in hand.     

A stable one-dimensional quasicrystal related to decagonal Al-Co-Ni

A stable one-dimensional quasicrystal has been found for Al-Co-Ni which is related closely to the decagonal phase in this system. It exists as a high-temperature state above 900 C in a range of compositions between approximately 71 and 71.5at.% Al between 18at.% and 22at.% Co. The modulation length along the periodic direction in its pseudo tenfold diffraction patterns is approximately 61A. We show that the 20A edge length defective rhomb tiling superimposed on to a corresponding high-resolution image, defined by centres of atomic clusters, can be considered as a subset of a phason-strained, 2.5A edge length Penrose tiling that has the observed period. An ideal 20A edge length tiling based on special configurations of this Penrose tiling can be chosen as a prototype for the observed experimental tiling.     

Penrose's New Argument

It has been argued, by Penrose and others, that Gödel's proof of his first incompleteness theorem shows that human mathematics cannot be captured by a formal system F: the Gödel sentence G(F) of F can be proved by a (human) mathematician but is not provable in F. To this argment it has been objected that the mathematician can prove G(F) only if (s)he can prove that F is consistent, which is unlikely if F is complicated. Penrose has invented a new argument intended to avoid this objection. In the paper I try to show that Penrose's new argument is inconclusive.     

Controllable electron-momentum filter in a δ-doped magnetically modulated semiconductor nanostructure

ABSTRACT

We have theoretically investigated the control of wave-vector filtering (WVF) by introducing δ-doping into a magnetically modulated nanostructure fabricated by depositing ferromagnetic stripes on top and bottom of a GaAs/Al_xGa_{1 ?x}As heterostructure. With the help of an improved transfer matrix method, the Schrödinger equation for electrons in this semiconductor nanostructure is solved exactly and the transmission efficient calculated numerically. We demonstrate that the WVF efficiency is associated closely with the weight and position of the δ-doping, which may be helpful for designing a controllable electron-momentum filter based on such a magnetically modulated semiconductor nanostructure.     

Constructive Logic with Strong Negation is a Substructural Logic. I

The goal of this two-part series of papers is to show that constructive logic with strong negation N is definitionally equivalent to a certain axiomatic extension NFL _ew of the substructural logic FL _ew . In this paper, it is shown that the equivalent variety semantics of N (namely, the variety of Nelson algebras) and the equivalent variety semantics of NFL _ew (namely, a certain variety of FL _ew -algebras) are term equivalent. This answers a longstanding question of Nelson [30]. Extensive use is made of the automated theorem-prover Prover9 in order to establish the result. The main result of this paper is exploited in Part II of this series [40] to show that the deductive systems N and NFL _ew are definitionally equivalent, and hence that constructive logic with strong negation is a substructural logic over FL _ew . Presented by Heinrich Wansing     

Phonon densities of states of gamma-cerium and delta-cerium measured by time-of-flight inelastic neutron scattering

Time-of-flight inelastic neutron scattering spectra were measured on cerium metal at temperatures near the fcc (gamma)-to-bcc (delta) transition temperature. Phonon density-of-states (DOS) curves were extracted from data acquired over a wide range of momentum transfers. A large softening of the phonon DOS was found in going from gamma-cerium to delta-cerium, and this accounts for an increase in vibrational entropy of (0.71 +/- 0.05)k _B/atom. To be consistent with the latent heat of the gamma-delta transition, this increase in vibrational entropy must be accompanied by a large decrease in electronic entropy. The results not only confirm the recent discovery of a significant electronic contribution to the gamma-delta transition but also suggest that it may be twice that previously reported.     

Remarks on Penrose’s “New Argument”

It is commonly agreed that the well-known Lucas–Penrose arguments and even Penrose’s ‘new argument’ in [Penrose, R. (1994): Shadows of the Mind, Oxford University Press] are inconclusive. It is, perhaps, less clear exactly why at least the latter is inconclusive. This note continues the discussion in [Lindström, P. (2001): Penrose’s new argument, J. Philos. Logic 30, 241–250; Shapiro, S.(2003): Mechanism, truth, and Penrose’s new argument, J. Philos. Logic 32, 19–42] and elsewhere of this question.     

My Art by the Numbers

The author explains his affinity for numbers as it relates to his work as an artist spanning his long career. This affinity helped him invent one of the first systems for making four-color digital prints. Having been only recently introduced to the book Number and Time, by Marie-Louise von Franz, the author finds that he is in full agreement with her depth psychology theories on number. Recounting a synchronicity that he experienced while writing this paper helped the author to understand Jung’s concept of the unus mundus, as explained by von Franz in Number and Time. He speculates that number archetypes must have evolved in human consciousness over very long periods of time and writes about the number zero as a “recent” example. The author also describes his experience of a spontaneous mathematical vision that led him to create an algorithm, which in turn led him to realize that crystals having fivefold symmetry could exist in nature, which was considered impossible at the time. The author discusses his new inventions of quasi-periodic and random tile patterns, which were inspired by 15th-century Islamic tile patterns, as they related to the aperiodic patterns invented by Roger Penrose in the 20th century. He speculates about the ability of artificially intelligent computer software to be able to generate random quasi-periodic patterns. Lastly, the author recounts a synchronistic experience that occurred during the month of his 72nd birthday, in which his work with numbers is seemingly reciprocated by nature.     

Cognitive Discrepancy,Dissonance, and Selective Exposure

Abstract

Although cognitive dissonance is regarded as one of the most recognized causes of selective exposure [N. J. Stroud, Niche News (Oxford University Press, 2011)], the mechanism for such causation is still unclear. By inducing dissonance in a web-based experiment, this study demonstrates how cognitive dissonance relates to information preferences—the intention to seek congruent information and the intention to seek incongruent information. The findings suggest that perceived hostility with respect to one’s belief (cognitive discrepancy) can enhance the intention to seek out for attitude-consistent information. More importantly, individuals were found to have the intention to avoid counterattitudinal information, but only when they experienced some sort of psychological discomfort (dissonance). In other words, while cognitive discrepancy leads individuals to crave for confirming information, only those who encounter negative emotions are likely to employ avoidance of disconfirming information as a dissonance-reduction strategy.     

Cosmic inflation and the past hypothesis

The past hypothesis is that the entropy of the universe was very low in the distant past. It is put forward to explain the entropic arrow of time but it has been suggested (e.g. [Penrose, R. (1989a). The emperor’s new mind. London:Vintage Books; Penrose, R. (1989b). Annals of the New York Academy of Sciences, 571, 249–264; Price, H. (1995). In S. F. Savitt (Ed.), Times’s arrows today. Cambridge: Cambridge University Press; Price, H. (1996). Time’s arrow and Archimedes’ point. Oxford: Oxford University Press; Price, H. (2004). In C. Hitchcock (Ed.), Contemporary debates in philosophy of science. Oxford: Blackwell]) that it is itself in need of explanation. It has also been suggested that cosmic inflation could provide the explanation, but Price (2004) raises a serious objection to this suggestion, which has otherwise received very little attention in the philosophical literature. Price points out that the standard inflationary explanation involves a double standard: although the evolution of the universe described by the inflationary model seems natural from the standard temporal perspective it looks highly unnatural from the reversed temporal perspective. The main purpose of this paper is to propose a novel form of the inflationary explanation that avoids this objection. It is argued that the inflationary model would not involve a double standard (but would still explain the past hypothesis) if we construct the model with a global “boundary” condition instead of a conventional boundary condition: if we assume that the universe is as generic as possible overall, rather than as generic as possible at some given point (e.g. the Big Bang) as is assumed in the standard inflationary model. This novel form of the inflationary explanation is then compared with Price’s 1996 preferred explanation, a version of the so-called “Weyl hypothesis”.     

Neck formation processes of nanocrystalline silicon carbide: A tight-binding molecular dynamics study

Atomistic and electronic structures in the process of intergranular neck formation of nanocrystalline silicon carbide (SiC) have been investigated by a tight-binding molecular dynamics method. An order-N parallel algorithm is employed for efficient calculations of electronic energy and forces. We find that a defect-free neck is formed between SiC nanocrystals aligned along [112] axis at T     

Health behaviour change theory meets falls prevention: Feasibility of a habit-based balance and strength exercise intervention for older adults

ObjectivesHabit formation is a proposed mechanism for behaviour maintenance. Very few falls prevention studies have adopted this as an intervention framework and outcome. Therefore, we tested feasibility of a theory-based behaviour change intervention that encouraged women to embed balance and strength exercises into daily life routines (e.g., eating, self-care routines).DesignThe EASY LiFE study was a mixed-methods, 4-month feasibility intervention that included seven group-based sessions and two telephone calls.Main outcome measuresWe obtained performance-based (i.e., Short-Physical-Performance-Battery) and psychological self-report measures (i.e., intention, self-efficacy, planning, action control, habit strength, quality of life) from 13 women at baseline (T1) and 4-month follow-up (T2). We applied the Framework-Method to post-intervention, semi-structured interviews to evaluate program content and delivery.ResultsIn total, 10 of 13 women completed the program (M_age = 66.23, SD = 3.98) and showed changes in their level of action control [mean difference_T1−T2 = 1.7, 95% CI (−2.2 to −0.8)], action planning [mean difference_T1−T2 = 0.8, 95% CI (−1.1 to −0.2)], automaticity [mean difference_T1−T2 = 2.5, 95% CI (−3.7 to −1.2)], and exercise identity [mean difference_T1−T2 = 2.0, 95% CI (−3.2 to −0.8)]. Based on the Theoretical Domains Framework we identified knowledge, behavioural regulation, and social factors as important themes. For program delivery, dominant themes were engagement, session facilitators and group format.ConclusionThe theory-based framework showed feasibility for promoting lifestyle integrated balance and strength exercise habits. Using activity and object-based cues may be particularly effective in generating action and automaticity.     

Investigating the Performance of Alternate Regression Weights by Studying All Possible Criteria in Regression Models with a Fixed Set of Predictors

We describe methods for assessing all possible criteria (i.e., dependent variables) and subsets of criteria for regression models with a fixed set of predictors, x (where x is an n×1 vector of independent variables). Our methods build upon the geometry of regression coefficients (hereafter called regression weights) in n-dimensional space. For a full-rank predictor correlation matrix, R _xx, of order n, and for regression models with constant R ² (coefficient of determination), the OLS weight vectors for all possible criteria terminate on the surface of an n-dimensional ellipsoid. The population performance of alternate regression weights—such as equal weights, correlation weights, or rounded weights—can be modeled as a function of the Cartesian coordinates of the ellipsoid. These geometrical notions can be easily extended to assess the sampling performance of alternate regression weights in models with either fixed or random predictors and for models with any value of R ². To illustrate these ideas, we describe algorithms and R (R Development Core Team, 2009) code for: (1) generating points that are uniformly distributed on the surface of an n-dimensional ellipsoid, (2) populating the set of regression (weight) vectors that define an elliptical arc in ℝ ⁿ , and (3) populating the set of regression vectors that have constant cosine with a target vector in ℝ ⁿ . Each algorithm is illustrated with real data. The examples demonstrate the usefulness of studying all possible criteria when evaluating alternate regression weights in regression models with a fixed set of predictors.     

Electrical conductivity of Nd and Ce co-doped Gd2Zr2O7 ceramics

In this study, (Gd_{1? x} Nd _x )₂(Zr_{1? x} Ce _x )₂O₇ (0 ≤ x ≤ 0.5) ceramics have been prepared by pressureless sintering at 1973 K to investigate the influence of Nd and Ce co-doping on their electrical conductivity. The electrical conductivity of the ceramics was investigated by impedance spectroscopy measurements from 723 to 1173 K over the frequency range of 20 Hz to 2 MHz in air. The measured values obey the Arrhenius relation. For each composition, the grain conductivity gradually increases with increasing temperature from 723 to 1173 K. At a given temperature, it gradually decreases with increasing neodymium and cerium contents from x = 0 to 0.3; thereafter, the grain conductivity exhibits a slight increase with further increasing neodymium and cerium contents up to x = 0.5.     

How people make decisions about predictive genetic testing: An analogue study

Abstract

Persons scoring high on negative affectivity (NA) have more subjective health complaints. In this study, we tested the hypothesis that high NA persons are more likely to experience internal sensations as threatening signs of health problems. Low and high NA participants (N=44) were given four breathing trials: one room air trial followed by three trials containing 5.5% CO₂ which induced transient low intensity somatic sensations. Prior to each CO₂ trial, participants received either positive, negative or uncertain labelings of the sensations that might occur. Participants rated the (un)pleasantness of the experienced somatic sensations and the perceived intensity. Also respiratory responses were measured. During CO₂ trials, reliable main effects of information were found but no effects involving NA were observed, neither on pleasantness ratings nor on respiratory responses. However, during room air breathing, high NA participants reported more intense somatic sensations than low NA participants. Post-experimental data suggested that high NA participants had more negative meanings and worries about the consequences of the physical sensations. It is concluded that interpretational biases in high NA is situated at the level of attributional processes.     

Arrangement of atomic clusters in a 2/1 cubic approximant in the Al-Zn-Mg alloy system

An arrangement of the so-called Bergman clusters of atoms in a 2/1 cubic crystalline approximant phase, which is closely related to Frank-Kasper-type icosahedral quasicrystals, in an Al-Zn-Mg alloy system is discussed in detail. The 2/1 cubic structure has eight Bergman clusters in its unit cell and the positions of the clusters can be understood as twelvefold sites in the 2/1 cubic approximant of the three-dimensional Penrose lattice. The atomic clusters are located at vertices of two types of rhombohedron, which are formed by six rhombic planes with an edge length of 3 1/2 a 2 /( 2 + 1) 1/2 and a shorter diagonal of 2 a 2 /( 2 + 1) 1/2 ( is the golden ratio and a is a quasilattice constant), which correspond to half a body diagonal and an edge length respectively of the 1/1 cubic approximant unit cell. The present results provide an important key for understanding the arrangements of atomic clusters in icosahedral quasicrystals.     

Mechanism, Truth, and Penrose's New Argument

Sections 3.16 and 3.23 of Roger Penrose's Shadows of the mind (Oxford, Oxford University Press, 1994) contain a subtle and intriguing new argument against mechanism, the thesis that the human mind can be accurately modeled by a Turing machine. The argument, based on the incompleteness theorem, is designed to meet standard objections to the original Lucas–Penrose formulations. The new argument, however, seems to invoke an unrestricted truth predicate (and an unrestricted knowability predicate). If so, its premises are inconsistent. The usual ways of restricting the predicates either invalidate Penrose's reasoning or require presuppositions that the mechanist can reject.     

A continuum model of deformation-twin dominant crack growth in fcc metals

A continuum model is proposed to address the effects of deformation twinning on ductile versus brittle fracture behaviour of low strain-hardening fcc metals after exhaustion of work hardening. Instead of discrete twin nucleation, a number of partial dislocations ahead of the tip exhibit themselves as twins at the final stage of failure. The crack-tip plasticity is amended for deformation twinning and the constitutive form for the flow strength of arrays of twins of the same sign is expressed as a second gradient of microrotation for their coupling. The twins not only shield the crack tip but also inhibit further dislocation emission to form a dislocation-free zone (DFZ) in the immediate vicinity of the tip. The stress fields induced by deformation twinning lead to fracture branching under Mode I loading. The model is borrowed from the conceptual model presented by Beltz et al. [Acta Mater. 44 3943 (1996)], based on the equivalence of the stresses derived from twin-based crack-tip plasticity, macroscopic plasticity and elasticity on the DFZ boundary. The DFZ size and the crack-tip shielding ratio are obtained, as well as the branching angle. The branching angle is noteworthy for low strain-hardening metals. A strong dependence of the toughness on intrinsic surface energy and hardening index is examined. The toughness reduction due to crack-tip constraints and in the ductile-to-brittle transition (DBT) temperature region is revisited and found to be in agreement with experimental observations and available predictions.     

No blank slates: Pre-existing schemas about pharmaceuticals predict memory for side effects

Objectives: Attribution of symptoms as medication side effects is informed by pre-existing beliefs about medicines and perceptions of personal sensitivity to their effects (pharmaceutical schemas). We tested whether (1) pharmaceutical schemas were associated with memory (recall/recognition) for side effect information (2) memory explained the attribution of a common unrelated symptom as a side effect.

Design: In this analogue study participants saw the patient leaflet of a fictitious asthma drug listing eight side effects.

Main outcome measures: We measured recall and recognition memory for side effects and used a vignette to test whether participants attributed an unlisted common symptom (headache) as a side effect.

Results: Participants who perceived pharmaceuticals as more harmful in general recalled fewer side effects correctly (r_{Correct Recall} = ?.273), were less able to differentiate between listed and unlisted side effects (r_{Recognition Sensitivity} = ?.256) and were more likely to attribute the unlisted headache symptom as a side effect (r_{side effect attribution} = .381, ps < .01). The effect of harm beliefs on side effect attribution was partially mediated by correct recall of side effects.

Conclusion: Pharmaceutical schemas are associated with memory for side effect information. Memory may explain part of the association between pharmaceutical schemas and the attribution of unrelated symptoms as side effects.