The Proofs Of The Grundgedanke In Wittgenstein's Tractatus

The Tractatus contains twodifferent proofs of the Grundgedanke, or thenonreferentiality of logical constants. In thispaper, I explicate the first proof in TLP 5.4s andreconstruct the less explicitly stated second proof. My explication of the first proof shows it to beelegant but based on an invalid inference. In myreconstruction of the second proof, the main argumentis that the sign of a logical constant does not denotebecause it possesses the punctuation-mark-nature. Andit possesses the punctuation-mark-nature because,given the analyticity thesis in TLP 5, one canestablish for everyday language an adequate symbolismwith N as the sole fundamental operation such that itssign is a bar indicating merely the order and scope ofits application.     

A theoretical frame of reference for family systems therapy? An introduction to Luhmann's theory of social systems

The starting point for this paper is that family therapy lacks a theoretical frame of reference of its own; thus a stepwise search for such a frame of reference is described. First, social systems are defined as communication systems. Second, it is shown in what way a family can be seen as a social system. With the help of the theory of social systems of the sociologist Luhmann, a theoretical frame of reference for systems therapy is drafted. Finally, we hint at the implications such a theoretical framework could have for clinical practice.     

Socrates questions Gorgias: The rhetorical vector of Plato's “Gorgias”

This essay argues that Plato's Gorgias, a dialogue lauding dialectic over rhetoric, uses a question-and-answer format as a heuristic of argument. Specific observations are advanced to explain the implications of Plato's techniques and to provide a more sensitive understanding of the process by which sought to gain the adherence of his readers.     

Tests of the generality of the principle of encoding specificity

Two empirical tests of the principle of encoding specificity are reported. In Experiment I, the normative strength of the cues presented on the input and on the recall trial was varied factorially. To lessen the emphasis on strictly associative learning, only half the items were cued in each phase of the study-recall cycle. Recall was higher when the cues remained the same than when they changed. However, regardless of the condition of input cuing, strong output cues were substantially more effective than weak ones. In Experiment II, the to-be-remembered words were shown in the presence of weak cues on the input trial. Recognition in the context of strong extralist cues was compared with recall to the original input cues. On the test of cued recognition, the target words were either generated by the subjects as free associates or presented to them as items on a test constructed by the experimenter. Contrary to previous findings, recall was not found to be superior to recognition. The phenomena of cue-dependent forgetting that have been interpreted as evidence for the principle of encoding specificity appear to have limited generality.     

On the estimation of parameters in latent structure analysis

In this note, we describe the iterative procedure introduced earlier by Goodman to calculate the maximum likelihood estimates of the parameters in latent structure analysis, and we provide here a simple and direct proof of the fact that the parameter estimates obtained with the iterative procedure cannot lie outside the allowed interval. Formann recently stated that Goodman's algorithm can yield parameter estimates that lie outside the allowed interval, and we prove in the present note that Formann's contention is incorrect.This research was supported in part by Research Contract No. NSF SOC 76-80389 from the Division of the Social Sciences of the National Science Foundation. The author is indebted to C. C. Clogg for helpful comments and for the numerical results reported here (see, e.g., Table 1).     

Liquid-specific stimulus properties can be used for haptic perception of the amount of liquid in a vessel put in motion

We investigated whether people can use haptic liquid-specific information made available by shaking the vessel containing the liquid. In experiment 1 we studied to what extent people can discriminate between liquid and solid substances and determine the amount of substance in the shaken vessel, as well as the effects of exploratory procedures on these abilities. Exploratory procedures including horizontal shaking of the vessel produced accurate identification of the content and more precise judgments for a liquid than for a solid, but vertical lifting produced an overestimation of the amount of liquid. In experiment 2 we demonstrated that people can discriminate between the amount of liquid and the amount of solid in the same vessel. Three theories of what liquid-specific stimulus properties are picked up by shaking the vessel are preliminarily examined.     

Three-month-olds' visual preference for faces and its underlying visual processing mechanisms

This study was aimed at investigating the face preference phenomenon and its underlying mechanisms at 3 months of age. Using an eye-tracker apparatus, Experiment 1 demonstrated that 3-month-olds prefer natural face images to unnatural ones, replicating and extending previous evidence obtained with schematic facelike stimuli. Experiments 2 and 3 showed that the general mechanisms that induce face preference in newborns could not explain the same phenomenon at 3 months of age, when infants are attracted by perceptual cues more specific to faces. This suggests that signs of a process of cognitive specialization are already present in 3-month-olds' visual behavior toward faces.     

Colour, polarity, disparity, and texture contributions to motion segregation

We measured how different cues are combined in motion-segregation processes by using motion stimuli where randomly distributed target dots were organised in global revolving motion while the remaining noise dots performed random motion. Target dots were cued with a different colour, polarity, disparity depth, or texture orientation than the noise dots, or they were the same as the noise dots. The stimuli were presented with a prolonged static cue preview which provided position cues to target dots or, briefly with static pre-target and post-target noise frames, which provided false position cues (no preview). All cues efficiently facilitated global motion segregation in cued-preview conditions. Colour completely failed to facilitate global motion segregation in no-preview conditions. Polarity and disparity facilitated segregation in no-preview conditions, although sensitivities were lower than in the preview conditions. Remarkably, texture orientation largely facilitated motion segregation by the same amount in both cued-preview and no-preview conditions. So, colour provides only position cues to the motion-segregation task whereas texture orientation, disparity, and to a lesser extent polarity are integrated with the segregation process.