Logical Truth and Tarskian Logical Truth

This paper examines the question of the extensional correctness of Tarskian definitions of logical truth and logical consequence. I identify a few different informal properties which are necessary for a sentence to be an informal logical truth and look at whether they are necessary properties of Tarskian logical truths. I examine arguments by John Etchemendy and Vann McGee to the effect that some of those properties are not necessary properties of some Tarskian logical truths, and find them unconvincing. I stress the point that since the hypothesis that Tarski's definitions are extensionally correct is deeply entrenched, the burden of proof is still on the shoulders of Tarski's critics, who have not lifted the burden. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of reinforcement rate and delay on the acquisition of lever pressing by rats.

The acquisition of lever pressing by naive rats, in the absence of shaping, was studied as a function of different rates and unsignaled delays of reinforcement. Groups of 3 rats were each exposed to tandem schedules that differed in either the first or the second component. First-component schedules were either continuous reinforcement or random-interval 15, 30, 60 or 120 s; second-component schedules were fixed-time 0, 1, 3, 6, 12, or 24 s. Rate of responding was low under continuous immediate reinforcement and higher under random-interval 15 s. Random interval 30-s and 60-s schedules produced lower rates that were similar to each other. Random-interval 120 s controlled the lowest rate in the immediate-reinforcement condition. Adding a constant 12-s delay to each of the first-component schedule parameters controlled lower response rates that did not vary systematically with reinforcement rate. The continuous and random-interval 60-s schedules of immediate reinforcement controlled higher global and first-component response rates than did the same schedules combined with longer delays, and first-component rates showed some graded effects of delay duration. In addition, the same schedules controlled higher second-component response rates in combination with a 1-s delay than in combination with longer delays. These results were related to those from previous studies on acquisition with delayed reinforcement as well as to those from similar reinforcement procedures used during steady-state responding.     

American women missionaries in the Gulf: Agents for cultural change

Arabia has figured in Western imagination from a very early time, but seldom in neutral terms. For reasons not thoroughly understood, the Arab role in Western thinking has fluctuated between hope and menace, love and hate. While nineteenth‐century Europe saw in Arabia a romantic adventure — an illustration of the Victorian era — nineteenth‐century America viewed it differently. It saw an alternation between the images of the supposedly fanatical Islam that at one time overran the Christian world and a deprived contemporary society in need of Christian aid. Plainly, Western images of Arabia have been more changeable than the conditions of Arab life. Perhaps one reason for this love/hate, menace/hope attitude lies in the fact that Islamic civilization has been the great alternative to Christendom. Being so different and also so distant, Arabia seemed like a cultural incognito, a place where Americans could start their intercultural experience. Nothing would bring them a step closer to their goal than missionary work.     

Ethical contexts of healing: Ecclesia and praxis

Conclusion We have suggested that the church is called to reflect the Reign of God. To do so it must engage in a process of careful reflection on its confession that Jesus is Lord. This calls for a relativization of all other communities, the recognition of the church as a community in its own right and the rejection of ethical individualism. To be a healing community it will need to discern a response to the mental health needs around us. In the third article in this series, I will focus on the character of healers that might emerge if we were to take more seriously the Reign of God as an ethical culture and the church as a discerning community.     

Children and adolescents discharged from public psychiatric hospital: Evaluation of outcome in a continuum of care

Ninety children and adolescents admitted to two state-operated psychiatric hospitals were followed from the time of their admission through one year post discharge. Data were collected from the children and adolescents, their families and clinicians at three intervals (during hospitalization, three months post discharge, and one year post discharge) to identify demographic, clinical, and service history characteristics of the children and adolescents, as well as to track their placement and other dispositional status following discharge from the hospital. The data indicated that the children and adolescents were seriously emotionally and behaviorally disturbed, came from families which were economically disadvantaged, and did not typically live in two-parent families. While the majority of the children and adolescents received recommended aftercare services during the three months following discharge from the hospital, there was a decline in placement stability for the children at the one-year post discharge followup. The most important predictors of successful outcome at discharge were living with a family member at the time of hospitalization and the participation of the family in the treatment planning during hospitalization.     

The diversity principle in the testing of arguments

According to the diversity principle of scientific reasoning, hypotheses receive greater confirmation when they are supported by diverse rather than similar sets of data. This article examines whether people reason like intuitive scientists by conforming to the diversity principle in the testing of arguments. The results of two experiments demonstrate that people do indeed conform to the diversity principle by choosing a set of diverse rather than similar premises to test the conclusion of an argument. These findings are discussed in terms of the different reasoning processes involved in argument evaluation, argument testing, and rule discovery.     

Problem syntezy sieci w logice progowej. I

Tre??: Wst?p. Cz??? pierwsza: Synteza sieci zbudowanych na elementach doprogowych. Rozdzia? I. Synteza sieci zbudowanych na elementach doprogowych w algebrze Boole'a: 1. Klasa elementów doprogowych. 2. Metoda Lindemana syntezy sieci. Rozdzia? II. Synteza sieci w logice doprogowej. 3. Aksjomatyka logiki doprogowej. 4. Podstawowe twierdzenia logiki doprogowej. 5. Zasadnicze twierdzenie logiki doprogowej. 6. Metody syntezy sieci w logice doprogowej. Cz??? druga: Synteza sieci zbudowanych na ogólnych elementach progowych. Rozdzia? I. Interpretacja geometryczna elementów progowych i funkcji algebry logiki: 1. Definicje i twierdzenia pomocnicze. 2. Interpretacja geometryczna ogólnych elementów progowych. 3. Definicje elementówn-wymiarowej kostki. 4. Interpretacja geometryczna funkcji algebry logiki. Rozdzia? II. Synteza siec_i jednego elementu progowego z pobudzaj?cymi wej?ciami: 5. W?asno?ci zbiorówA iB oraz ich zbiorów oporowychA _o iB _o. 6. Równanie hiperp?aszczyzny ?ci?le oddzielaj?cej zbiórB _o od zbioruA _o. 7. Warunki realizacji funkcji na progowych elementach z pobudzaj?cymi wej?ciami. 8. Metody syntezy progowego elementu z pobudzaj?cymi wej?ciami. Rozdzia? III. Synteza sieci jednego ogólnego elementu progowego: 9. Uogólnienie twierdzeń dla elementów progowych z pobudzaj?cymi i hamuj?cymi wej?ciami. 10. Warunki realizacji funkcji jednym ogólnym elementem progowym. 11. Metody syntezy jednym ogólnym elementem progowym. Rozdzia? IV. Synteza sieci zbudowanych na ogólnych elementach progowych: 12. Synteza sieci rz?du pierwszego i drugiego. 13. Synteza sieci rz?du trzeciego i sieci wy?szych rz?dów. Zakończenie. Dodatek: Progowe funkcjen≤4 zmiennych. Bibliografia.     

Comparisons of some learning models for response bias in signal detection

The effects of variations in signal probability and varying degrees of correct feedback on response bias were studied in a yes-no auditory signal detection task. The main finding was that the bias towards saying yes was an increasing function of the frequency of signal feedback events, but did not depend on the correctness of the feedback. Several learning models coupled with a simple psychophysical and decision model yielded predictions about overall biases and certain sequential statistics. Only one model, which can be decribed as an “informational” model, gave a good account of both observed overall biases and sequential statistics. This model assumes the observer’s response bias is strengthened for the feedback-reinforced response when the observer’s sensory information is ambiguous or is contradicted by the feedback information.