Negation as Cancellation, and Connexive Logic

Of the various accounts of negation that have been offered by logicians in the history of Western logic, that of negation as cancellation is a very distinctive one, quite different from the explosive accounts of modern "classical" and intuitionist logics, and from the accounts offered in standard relevant and paraconsistent logics. Despite its ancient origin, however, a precise understanding of the notion is still wanting. The first half of this paper offers one. Both conceptually and historically, the account of negation as cancellation is intimately connected with connexivist principles such as ¬( ¬). Despite this, standard connexivist logics incorporate quite different accounts of negation. The second half of the paper shows how the cancellation account of negation of the first part gives rise to a semantics for a simple connexivist logic.     

Attachment as an Integrating Concept in Couple and Family Therapy: Some Considerations with Special Reference to South Africa

Couples, marital, and family therapy in South Africa and throughout the world have undergone radical changes in theory and practice in the last three to four decades. These developments are seen in the emergence of different approaches which may be regarded as modern or post-modern, intrapsychic or systemic. While these different approaches are often seen as theoretically and clinically incompatible, it is the aim in this paper to suggest that the time has come to seek points of integration of these different approaches, and the construct of attachment is proposed as an ideal integrating concept. Two case illustrations are used to demonstrate attachment as an integrating concept. It is suggested that the concept of attachment may also be applied to family therapists and associations, including and especially in South Africa.     

Boolean negation and all that

Conclusion We have seen that proofs of soundness of (Boolean) DS, EFQ and of ABS — and hence the legitimation of these inferences — can be achieved only be appealing to the very form of reasoning in question. But this by no means implies that we have to fall back on classical reasoning willy-nilly. Many logical theories can provide the relevant boot-strapping. Decision between them has, therefore, to be made on other grounds. The grounds include the many criteria familiar from the philosophy of science: theoretical integrity (e.g., paucity of ad hoc hypotheses), adequacy to the data (explaining the data of inference —all inferences, not just those chosen from consistent domains!) and so on. This paper has not attempted to address these issues in general. All it demonstrates is that the charge that a dialetheist solution to the semantic paradoxes can be maintained only by making some intelligible notion ineffable cannot be made to stick. The dialetheist has a coherent position, endorsing the T-scheme, but rejecting DS, EFQ (even Boolean DS and EFQ) and ABS. And any argument to the effect that the relevant notions are both ineffable and intelligible begs the question. The case against consistent solutions to the semantic paradoxes therefore remains intact.     

Backwards causation and the permanence of the past

Can a present or future event bring about a past event? An answer to this question is demanded by many other interesting questions. Can anybody, even a god, do anything about what has already occurred? Should we plan for the past, as well as for the future? Can anybody precognise the future in a way quite different from normal prediction? Do the causal laws and the past jointly preclude free action? Does current physical theory entail a consistent version of backwards causation? Recent articles on the problem of backwards causation have drawn attention to the importance of the principle of the fixity of the past: that the past is now fixed. It can be shown that the standard argument against backwards causation (the bilking experiment) simply builds in the assumption of past fixity. A fixed past deprives future events of past efficacy. This has naturally led to the speculation that by abandoning past fixity real power over the past may be possible. In this paper I show that in order to have an interesting thesis of backwards causation it is not enough simply to drop past fixity. More must go. In particular, to ensure what could be called future-to-past efficacy we must abandon two entrenched principles of permanence: the principle of permanent fixity, and the principle of permanent truth. The only alternative for backwards causal theorists is to embrace real contradictions in nature.     

A tactile stimulation device for measuring two-point and gap discrimination thresholds in humans

A device to measure two-point-discrimination and gap-discrimination thresholds is described. The apparatus is capable of controlled and reliable delivery of forces up to 42.50 g while determining point of skin contact and subsequent depth of skin indentation during threshold determination. Stimulus delivery is controlled by computer software that deactivates a solenoid, allowing a counterbalanced beam with one of two stimulus wheels mounted on its end to rise and stimulate the skin. Depth of skin indentation is recorded by hardware that monitors the output of a photocell reflecting the position of the beam. The apparatus allows complete computer control of all data acquisition and recording.     

The Masculinity-Femininity Scale of MMPI-2: is it useful with normal men?

Using ratings provided by significant others, we examined characteristics of 819 normal men whose scores on the Masculinity-Femininity scale (Scale 5) of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) ranged from low to high. Also examined were the possible effects of educational level as a moderator variable. Only one external characteristic was correlated with Scale 5 scores at a level of significance that could not be attributed to chance, and that correlation was negative, whereas previous literature indicated a positive relationship. The findings were essentially the same whether or not the effects of education were controlled. Regardless of Scale 5 scores and the higher the men's educational levels, the more positive were ratings by their partners. In general, the results do not support the usefulness of Scale 5 in describing the personalities and behaviors of normal men.