Sorites Is No Threat to Modus Ponens: A Reply to Kochan

A recent article by Jeff Kochan contains a discussion of modus ponens that among other thing alleges that the paradox of the heap is a counterexample to it. In this note I show that it is the conditional major premise of a modus ponens inference, rather than the rule itself, that is impugned. This premise is the contrapositive of the inductive step in the principle of mathematical induction, confirming the widely accepted view that it is the vagueness of natural language predicates, not modus ponens, that is challenged by Sorites.     

Spatial cognition in the gerbil: computing optimal escape routes from visual threats

Previous studies in our laboratory have shown that when presented with a sudden stimulus simulating an oncoming predator, Mongolian gerbils can compute the optimal trajectory to a safe refuge, taking into account the position of the threat, the location of a clearly visible refuge, and several other contextual variables as well. In the present studies, the main goal was to explore the abilities of gerbils to use mental representations of spaces that were visually occluded by opaque barriers to compute efficient escape trajectories. In all studies, gerbils were placed into a round open field containing a single refuge. On each trial, an overhead visual stimulus was caused to ‘fly’ overhead, eliciting robust escape movements from the gerbils. By manipulating the shape and position of a series of opaque barriers that were interposed between the gerbils and the refuge, we were able to show that gerbils can compute the shortest route to an invisible target, even when the available routes to the target are made complex by using elaborate barrier shapes. These findings suggest that gerbils can maintain representations of their locations with respect to salient environmental landmarks and refuges, even when such locations are not continuously visible.     

Can logic be combined with probability? Probably

In the nineteen sixties seminal work was done by Gaifman and then Scott and Krauss in adapting the concepts, tools and procedures of the model theory of modern logic to provide a corresponding model theory in which notions of probabilistic consistency and consequence are defined analogously to the way they are defined (semantically) in the deductive case. The present paper proposes a way of extending these ideas beyond the bounds of a formalised language, even the infinitary language of Scott and Krauss, to achieve a logic having the power and expressiveness of the modern mathematical theory of probability.     

The Unity of a Tractarian Fact

It is not immediately clear from Wittgenstein’s Tractatus how to connect his idea there of an object with the logical ontologies of Frege and Russell. Toward clarification on this matter, this paper compares Russell’s and Wittgenstein’s versions of the thesis of an atomic fact that it is a complex composition. The claim arrived at is that whilst Russell (at times at least) has one particular of the elements of a fact – the relation – responsible for the unity of the whole, for Wittgenstein the unity of a fact is the product of copulative powers inherent in all its elements. All kinds of constituents of Tractarian facts – all kinds (forms) of object – are, to use Fregean terminology, unsaturated.     

Use of the Sleep Assessment Device (Kelley and Lichstein, 1980) to validate insomniacs' self-report of sleep pattern

A comparison is presented of insomniacs' self-reported sleep pattern and objectively monitored sleep using the Sleep Assessment Device (SAD; Kelley & Lichstein, 1980). Analysis of 110 subject nights revealed modest but significant subjective overestimates of both sleep latency and sleep duration which were accounted for by the demands of the task (i.e., longer time periods are harder to estimate accurately). Correlations between self-report and SAD measures were, however, consistently high, suggesting that self-report may be a valid index of sleep disturbance. Results are discussed with reference to the clinician's task in evaluating sleep complaints.This research stury was supported by a grant from the Research Fund of Lanarkshire Health Board, Scotland.     

Feminist Developmental Theory: Implications for Counseling

This article discusses the importance of counseling guided by a life-span development model. Major developmental tasks across the life span are outlined from an Eriksonian perspective. This is contrasted with the feminist development theory of S. Conarton and L. Kreger-Silverman (1988). Issues covered include the call by C. Gilligan (1991) for counselors to assist women to reclaim their intuitive voice and the importance of connectedness for women's development in Western society. Implications for counseling are explored with reference to borderline personality disorder and anorexia nervosa.     

Altruism: A Social Science Chameleon

The self-interest paradigm that has dominated and defined social science is being questioned today in all the social sciences. Frontline research is represented by C. Daniel Batson's experiments, which claim to present empirical evidence of altruism. Impressive though this is against the background of the self-interest paradigm, its ultimate significance might be to illustrate the inadequacy of social science to deal with a transcendent reality like altruism.     

Effects of US-Alone Presentations on Human Evaluative Conditioning

In the context of evaluative conditioning, the effects of additional presentations of the unconditioned stimulus (US) prior to conditioning (US preexposure) or after conditioning (US postexposure) were examined using between- and within-subjects control conditions. Two experiments that differed with respect to the nationality of the subjects were conducted. In both experiments, US-alone presentations reduced the magnitude of the evaluative response. The US pre- and postexposure effects were observed in subjects classified as aware as well as in subjects classified as unaware of the experimental contingencies. Another finding is that the evaluative conditioning procedure described by Martin and Levey (1978; Levey & Martin, 1975) resulted in reliable conditioning effects also in an American sample, thus extending the scope of that special evaluative conditioning paradigm. The findings are discussed in the context of recent models of classical and evaluative conditioning. Especially, the unexpected US postexposure effect gives rise to speculations concerning the learning process underlying evaluative conditioning.