The Idea of a Proof-Theoretic Semantics and the Meaning of the Logical Operations

This is a purely conceptual paper. It aims at presenting and putting into perspective the idea of a proof-theoretic semantics of the logical operations. The first section briefly surveys various semantic paradigms, and Section 2 focuses on one particular paradigm, namely the proof-theoretic semantics of the logical operations. This revised version was published online in June 2006 with corrections to the Cover Date.     

Diamonds are a Philosopher's Best Friends

The knowability paradox is an instance of a remarkable reasoning pattern (actually, a pair of such patterns), in the course of which an occurrence of the possibility operator, the diamond, disappears. In the present paper, it is pointed out how the unwanted disappearance of the diamond may be escaped. The emphasis is not laid on a discussion of the contentious premise of the knowability paradox, namely that all truths are possibly known, but on how from this assumption the conclusion is derived that all truths are, in fact, known. Nevertheless, the solution offered is in the spirit of the constructivist attitude usually maintained by defenders of the anti-realist premise. In order to avoid the paradoxical reasoning, a paraconsistent constructive relevant modal epistemic logic with strong negation is defined semantically. The system is axiomatized and shown to be complete.     

The Ethical Challenges of the Digital Age

This article examines the ethical challenges of digital transformation in three steps. First, it offers a survey of the various dimensions of digital transformation and the ethical challenges that are associated with them: the exposure of private life through access to data; the change of communication culture through algorithms; the concentration of corporate power; changes in the world of work; the military use of digital technology; and the fusion of the human being and the machine. Second, it reflects upon various fundamental anthropological dimensions of the biblical tradition, which does not define humankind through itself but first and foremost in relation to, and being different from, God. Third, it draws conclusions about how to deal with digital transformation: through rescuing public discourse, making digital transformation socially accountable, and offering a perspective of theological anthropology that takes account of both the vulnerability and the deep freedom of our humanity.     

Investigating the Relationships Between Mobility Behaviours and Indicators of Subjective Well-Being Using Smartphone-Based Experience Sampling and GPS Tracking

People interact with their physical environments every day by visiting different places and moving between them. Such mobility behaviours likely influence and are influenced by people's subjective well-being. However, past research examining the links between mobility behaviours and well-being has been inconclusive. Here, we provide a comprehensive investigation of these relationships by examining individual differences in two types of mobility behaviours (movement patterns and places visited) and their relationship to six indicators of subjective well-being (depression, loneliness, anxiety, stress, affect, and energy) at two different temporal levels of analysis (two-week tendencies and daily level). Using data from a large smartphone-based longitudinal study (N = 1765), we show that (i) movement patterns assessed via GPS data (distance travelled, entropy, and irregularity) and (ii) places visited assessed via experience sampling reports (home, work, and social places) are associated with subjective well-being at the between and within person levels. Our findings suggest that distance travelled is related to anxiety, affect, and stress, irregularity is related to depression and loneliness, and spending time in social places is negatively associated with loneliness. We discuss the implications of our work and highlight directions for future research on the generalizability to other populations as well as the characteristics of places. © 2020 European Association of Personality Psychology     

Effects of reward magnitude and training frequency on the learning rates and memory retention of the Port Jackson shark Heterodontus portusjacksoni

Animal Cognition - The development of adaptive responses to novel situations via learning has been demonstrated in a wide variety of animal taxa. However, knowledge on the learning abilities of one...     

Visual timing abilities of a harbour seal (Phoca vitulina) and a South African fur seal (Arctocephalus pusillus pusillus) for sub- and supra-second time intervals

Animal Cognition - Timing is an essential parameter influencing many behaviours. A previous study demonstrated a high sensitivity of a phocid, the harbour seal (Phoca vitulina), in discriminating...     

Use of Vacuum Tube Amplification in Establishing Differential Motor Reactions

1. The electromyographic potentials arising from masticatory movements were picked up by electrodes chronically implanted in the brains of eight rats. The rats had been trained in a Skinner box to press a lever for food reinforcement on a 100 per cent schedule. Lever and food cup were separated by 180[ddot] in a cylindrical metal box one foot in diameter.

2. The problem was to determine whether thoroughly trained animals would show AGRs as determined by the presence of electromyographic potentials when, in the course of pressing, food was suddenly withheld. Only two of the eight animals gave an AGR during the extinction process, and in one of these the phenomenon was minimal.

3. In the discussion it is pointed out that the absence of AGRs in the animals was possibly related to the short time interval intervening between depression of the lever and securing the food-pellet reward.