Multiple and iterated contraction reduced to single-step single-sentence contraction

Multiple contraction (simultaneous contraction by several sentences) and iterated contraction are investigated in the framework of specified meet contraction (s.m.c.) that is extended for this purpose. Multiple contraction is axiomatized, and so is finitely multiple contraction (contraction by a finite set of sentences). Two ways to reduce finitely multiple contraction to contraction by single sentences are introduced. The reduced operations are axiomatically characterized and their properties are investigated. Furthermore, it is shown how iterated contraction can be reduced to single-step, single-sentence contraction. However, in this framework the outcome of iterated contraction depends unavoidably on the order in which the inputs are received. This order-dependence makes it impossible to treat two inputs on an equal footing. Therefore it is often preferable to perform changes involving several pieces of information as multiple rather than iterated change.     

Coherence in Epistemology and Belief Revision*

A general theory of coherence is proposed, in which systemic and relational coherence are shown to be interdefinable. When this theory is applied to sets of sentences, it turns out that logical closure obscures the distinctions that are needed for a meaningful analysis of coherence. It is concluded that references to “all beliefs” in coherentist phrases such as “all beliefs support each other” have to be modified so that merely derived beliefs are excluded. Therefore, in order to avoid absurd conclusions, coherentists have to accept a weak version of epistemic priority, that sorts out merely derived beliefs. Furthermore, it is shown that in belief revision theory, coherence cannot be adequately represented by logical closure, but has to be represented separately. *Contribution to “Seven Bridges”     

Does singing promote well-being?: An empirical study of professional and amateur singers during a singing lesson

This study explored the possible beneficial effects of singing on well-being during a singing lesson. Eight amateur (2m, 6f, age 28–53 yrs) and eight professional (4m, 4f, age 26–49 yrs) singers who had been attending singing lessons for at least six months were included. Continuous ECG was recorded and computerized spectral analysis was performed. Serum concentrations of TNF-alpha, prolactin, cortisol, and oxytocin were measured before and 30 min after the lesson. Five visual analogue scales (VAS, sad-joyful, anxious-calm, worried-elated, listless-energetic, and tense-relaxed) were scored before and after the lesson. In addition, a semi-structured interview was performed. Heart rate variability analyses showed significant changes over time in the two groups for total power, and low and high frequency power. Power increased during singing in professionals, whereas there were no changes in amateurs. This indicates an ability to retain more “heart-brain connection,” i.e., more cardio-physiological fitness for singing in professional singers, compared to amateur singers. Serum concentration of TNF-alpha increased in professionals after the singing lesson, whereas the concentration in amateurs decreased. Serum concentrations of prolactin and cortisol increased after the lesson in the group of men and vice versa for women. Oxytocin concentrations increased significantly in both groups after the singing lesson. Amateurs reported increasing joy and elatedness (VAS), whereas professionals did not. However, both groups felt more energetic and relaxed after the singing lesson. The interviews showed that the professionals were clearly achievement-oriented, with focus on singing technique, vocal apparatus and body during the lesson. The amateurs used the singing lessons as a means of self-actualization and self-expression as a way to release emotional tensions. In summary, in this study, singing during a singing lesson seemed to promote more well-being and less arousal for amateurs compared to professional singers, who seemed to experience less well-being and more arousal.