Truthlikeness without truth: A methodological approach

In this paper, an attempt is made to solve various problems posed to current theories of verisimilitude: (1) the (Miller's) problem of linguistic variance; (2) the problem of which are the best scientific methods for getting the most verisimilar theories; and (3) the question of the ontological commitment in scientific theories. As a result of my solution ot these problems, and with the help of other considerations of epistemological character, I conclude that the notion of Tarskian truth is dispensable in a rational (and realist) interpretation of the scientific enterprise. As a logical result, however, falsificationism will be vindicated.

... and in brief, a speaker must always aim at verisimilitude, and send the truth packing.

Plato,Phaedrus, 272 EI want to express my gratitude to Professors García-Bermejo, Niiniluoto, and Zofío for interesting comments and critiques of several of the ideas in this paper, and to Miss Karen Firnich for correcting my English. I am also thankful to an anonymous referee who indicated several dark points on a previous version of my article.     

A biopsychosocial model for treating infertility

With approximately one out of six married couples experiencing infertility, having a basic knowledge of infertility is important to marriage and family therapists. This paper presents important themes that infertile couples often struggle with and stresses the importance of having a biological, psychological, and social understanding of infertility. In addition, the paper suggests possible interventions that family therapists can use in helping infertile couples.     

Visual perception of surface curvature: psychophysics of curvature detection induced by motion parallax

The continuous approach to optic-flow processing shows that the curvature of a moving surface is related to a second spatial derivative of the velocity field, the spin variation (Droulez & Cornilleau-Pérès, 1989). With this approach as a theoretical framework, visual sensitivity to the curvature of a cylinder in motion was measured using a task of discrimination between cylindrical and planar patches. The results confirm the predictions suggested by the theory: (1) Sensitivity to curvature was always greater when the cylinder axis and the frontal translation were parallel than when they were orthogonal. The ratio of curvature detection thresholds in the two cases was between 1.3 and 2.5; the value predicted from the spin variation theory is about 2. (2) Sensitivity to curvature increased strongly with the velocity of the motion but was only weakly affected by its amplitude and the duration of viewing for the range of values used in our experiments.     

Splitting visual space with attention

If a right-left spatial compatibility effect is observed, it can be maintained that the space has been segmented into right- and left-side parts. The present study aimed at showing a spatial compatibility effect (and, by implication, a right-left subdivision of space) solely attributable to the orienting of attention. Five groups of 8 normal subjects were required to give right-left discriminative responses to stimuli presented within one of six empty boxes arranged in a horizontal row. Reaction times and errors were recorded. The first two experiments showed that a right-left grouping of the boxes occurred regardless of whether subjects' fixation was kept at the intermediate position (Experiment 1) or at one extremity (Experiment 2) of the row. In Experiments 3 and 4, subjects' attention was not aligned with a fixed position but was moved, through peripheral cues, from trial to trial and positioned between different pairs of adjacent boxes. The results showed that the display was again subdivided into two regions and that the reference point for the right-left subdivision was the focus of attention. In Experiment 5, eye position was instrumentally monitored, and subjects' attention was directed by central cues. The results confirmed that the focusing of attention leads to a right-left partitioning of space, with the boundary at the locus of focal attention. In conclusion, we demonstrated, by employing a right-left spatial compatibility paradigm, that directing attention to a position in space brings about a right-left perceptual organization that predominates over that provided by the other egocentric reference axes.     

The physiology of the tunnel

Several theories to account for the origin of tunnel hallucinations and tunnel experiences near death are considered: (1) the idea of a real tunnel; (2) representations of transition; (3) reliving birth memories; (4) imagination; and (5) physiological origins. Three different physiological theories are considered that related the tunnel form to the structure of the visual cortex. All can account for much of the phenomenology of the tunnel experience, and all lead to testable predictions. It is argued that the tunnel experience involves a change in the mental model of the self in the world. Because of this, an experience of purely physiological origin, with no implications for other worlds or for survival, can nevertheless produce lasting changes in the sense of self and reduce the fear of death.     

Comparative clinicogenetic study of schizophrenic psychoses

The author diagnoses 350 carefully selected schizophrenic subjects, their parents and their siblings during parallel studies using three different clinical classification systems and analyzes the results by multiple threshold analysis and the multifactorial inheritance model. The results suggest that, of the three classifications the author studied, Leonhard's and Sneshnewski's system yield relatively homogeneous subgroups; this indicates the future significance of these nosological systems for the planning of biopsychiatric research.