Versuche zur Bestimmung der Abhängigkeit der Unterschiedsschwelle einer geometrischen Grössendimension von der Intensität bei verschiedener schwacher, nahe der absoluten Intensitätsschwelle liegender Lichter. Im Gegensatz zu den komplizierten Formeln, die die Abhängigkeit bei höheren Lichtintensitäten dargeben, gilt nahe der Minimalschwelle der Intensität ein bilinearer Ausdruck der Invarianz des Produkts der Reizunterschiedsschwelle der Grössendimension und der Lichtintensität . Die Bedeutung des Befundes im Zusammenhang mit früheren ähnlichen Ergebnissen wird besprochen.Experiments on determination of the difference threshold of visual size using different, weak lights, (...) near the absolute intensity threshold, are presented. Contrary to the complicated formulae obtained when the light is bright, near the minimal intensity threshold a simple bilinear equation holds true: the product of the stimulus threshold of visual size and the intensity threshold is found to be invariant. The significance of the findings are discussed in connection with similar, previous results.Des expériences pour déterminer le seuil spatial différentiel , en utilisant différentes lumières faibles, à la limite du seuil de l'intensité absolue, sont exposées. Contrairement aux formules compliquées qu'onn obtient avec des lumières intenses, près du seuil minime de l'intensité, une simple expression bilinéaire est valable: le produit du seuil spatial et du seuil de l'intensité est invariable. La signification de ce fait est discutée, en même temps que des résultats analogues antérieurs. (shrink)

In this essay I investigate the interplay between actual and potential properties of a thing within an Aristotelian conceptual framework. A minimal formal treatment of such interplay is proposed, outlining the actual or possible causal impact of these properties with respect to the changes of a thing in question. I also mention the historically interesting controversy between Aristotle and the Megarians concerning the relationship between power and act, as well as Hintikka’s application of the Principle of Plenitude. The essay ends (...) with certain suggestions for treating the problems of actual and potential properties by means of dispositions and contrary-to-fact conditionals. (shrink)

There are two fundamental questions concerning the choice and presence of objects in various formal systems: Where do these objects come from? What do we know about them? To answer these questions I introduce the notion of a proto-ontology as the pre-theoretic realm of entities from which the basic objects – individuals – of the formal system S are postulated. The pragmatic aspects of such choices are investigated with regard to first-order logic, both pure and applied, set theory and mereology. (...) It is claimed that the postulated objects enter the formal system S with a package of properties and relationships, the recognition of which depends on the interpretation and application of the available predicates of S. If these properties and relationships are not made explicit, a possible clash may arise between them and the properties and relationships “assigned” to the individuals of S by the interpreted predicates of S. As regards the relationship between logic and metaphysics, I contend that logic can perhaps be viewed as the articulation of the fundamental features of proto-ontological objects without which no discourse or theory would be possible. In this sense logic could also be viewed as a theory and method of the construction of a well-articulated metaphysical theory. (shrink)

When A. J. Ayer commented on Russell’s theory of acquaintance, he claimed that the person who is acquainted with an object knows that the object exists and also that the object in question has the properties which it appears to have. This essay employs Russell’s theory of knowledge by acquaintance from the period between 1910 and 1918 and critically analyzes both the existential and the descriptive statements as they are related to the object of acquaintance. In particular, Ayer’s views on (...) the relationship between appearance and reality are treated as unacceptable from any sound epistemological point of view. I believe that the logical analysis of these epistemological problems reveals intricate issues involved in such discussions, which transcend their limited historical context. (shrink)

In this essay, I investigate the dynamic foundations of Hume’s philosophy which is so heavily dependent upon Newton’s physics. Hume’s ubiquitous phrase „force and vivacity” is symptomatic of his dynamic, rather than voluntaristic, position that dominates his interpretation of impressions, ideas, and causality in particular. After pointing out some inconsistencies of Hume’s Newtonism, I concentrate on Hume’s treatment of power. It is a well-known fact that Hume rejected natural powers, in fear of their occult character, but accepted human powers giving (...) them an actualist interpretation. I suggest that there is a dispositional treatment hidden in Hume’s statements which puts Hume in line with other philosophers of power. (shrink)

Roku 1906 Łukasiewicz uverejnil podnetný návrh na logický výklad kauzálneho vzťahu pomocou pojmu nevyhnutnosti a jednoduchej závislosti. Uplatnil v ňom zákon transpozície, známy z výrokovej logiky, a modálne úvahy . Vo svojej historicky motivovanej analýze Łukasiewiczovho návrhu autor ukazuje, že Łukasiewiczovi sa nepodarilo oddeliť vzťah príčiny a účinku od vzťahu dôvodu a dôsledku, ani špecifikovať príslušné modality. Napriek tomu Łukasiewicz si zaslúži uznanie za pioniersky pokus traktovať tradičný filozofický problém kauzality netradičnými prostriedkami logiky relácií.

This historically oriented article describes Whiteheadś life-long concern with logic. Although his creative phase in logic seemed to have ended with the publication of Principia Mathematica, he remained continuously interested in logic of relations and theory of events and even as a speculative metaphysician appreciated logic as - in his words - his "first love".

Russell’s distinction between knowledge by acquaintance and knowledge by description has been recently re-examined in frequently controversial epistemo-logical contributions. The present essay reflects upon the pertinent papers by D. F. Pears, J. Hintikka, R. Chisholm, W. Sellars, A. J. Ayer, and others, but is pri-marily founded on Russell’s significant formulations from his writings published between 1910 and 1918. By employing an auxiliary device of a late-Wittgen-steinian language game, I explore at first the situation in which human subject is “experiencing” and (...) naming particular objects and later the subject’s acquaintance with universals. The reconstruction of such situations shows that, contrary to Russell’s assumptions, even the “purest” acquaintance cannot function without knowledge by description, i.e. without sta-ting propositions about the object of acquaintance . Then the only “descriptionless” alternative would be a kind of intuitive knowledge of such objects which is difficult to reconcile with the position held by Russell in the 1910s. Whatever the consequences, this topic retains its fundamental epistemological significance. (shrink)

Many philosophers have attempted to offer a logical theory of objects, employing different techniques. Thus R. Carnap tried to “reconstruct” logically the world by using the modern symbolic logic, while N. Goodman “constructed” the world with the help of the calculus of individuals or the logic of part-whole relations. W.V. Quine helped to steer the attention toward the question of ontological commitment and toward a theory of objects produced by a logical analysis of natural languages. Recently, there have been controversial (...) discussions concerning the metaphysical and logical aspects of objects in actual and possible worlds as well as new contributions to the theory of nonexistent objects, rekindling the old Russell-Meinong controversy. It seems that even the proposed theories of events, such as that of R. M. Martin, maintain the great significance of the notion of an object. Then there is a plethora of the so-called intensional objects, such as the alleged objects of propositional attitudes, the story of which is tied with the names of Frege, Russell, Carnap and many others. Is it possible to give an all-embracing theory of objects which would satisfy all the parties involved? Although such possibility may be very questionable, the instrumental role of logic for the development of the metaphysical theories of objects is indisputable. Two factors are, however, involved in the constitution of a logical theory of objects: the basis or the given data from which the theory starts; the logical apparatus employed, i.e., the logical axioms and rules of inference, just as the relevant semantical rules which are formulated in the metalanguage. While the logical apparatus is usually very clear, at least in the case of the formally well-construed theories, the given basis of a metaphysical theory T—as we may call it—might contain many tacit assumptions which would need a lot of clarification. It seems that philosophers fight more about the presuppositions and assertions of their systems than about the logic involved. I would like to discuss the interplay between the above two factors, starting with the realm of the given objects. As to the second factor—the logical apparatus involved—the contributions of first-order predicate logic and of the calculus of individuals will be considered. (shrink)

A propositional interpretation of knowledge by acquaintance seems more promising than the nonpropositional one, endorsed by Russell. According to the propositional interpretation, to be acquainted with an object means to attend (pay attention) to individuating features of the object. For the actual, direct acquaintance with an object, a subject's perception of the object and his attending to the individuating features of it (just as the fact that these features do belonge to the object in question) are the essential factors. Proper (...) names of objects and subject's memory images referring to objects of acquaintance may be viewed as their special individuating features (in spite of being attached to these objects "externally"). For the dispositional (non-actual) notion of acquaintance, a relativization of time must be added, together with the subject's ability to attend to the individuating features of the object under proper conditions (when the object of previous acquaintance is presented or represented to the subject). Although the conditional formulas expressing these situations contribute to the explication of the concept of knowledge by acquaintance, their truth-status remains open and contingent upon the ways of solving the problem of individuation (identification). (shrink)

A propositional interpretation of knowledge by acquaintance seems more promising than the nonpropositional one, endorsed by Russell. According to the propositional interpretation, to be acquainted with an object means to attend (pay attention) to individuating features of the object. For the actual, direct acquaintance with an object, a subject's perception of the object and his attending to the individuating features of it (just as the fact that these features do belonge to the object in question) are the essential factors. Proper (...) names of objects and subject's memory images referring to objects of acquaintance may be viewed as their special individuating features (in spite of being attached to these objects "externally"). For the dispositional (non-actual) notion of acquaintance, a relativization of time must be added, together with the subject's ability to attend to the individuating features of the object under proper conditions (when the object of previous acquaintance is presented or represented to the subject). Although the conditional formulas expressing these situations contribute to the explication of the concept of knowledge by acquaintance, their truth-status remains open and contingent upon the ways of solving the problem of individuation (identification). (shrink)

We calculate the Lebesgue–measures of the stability sets of Nash-equilibria in pure coordination games. The results allow us to observe that the ordering induced by the Lebesgue–measure of stability sets upon strict Nash-equilibria does not necessarily agree with the ordering induced by risk–dominance. Accordingly, an equilibrium selection theory based on the Lebesgue–measure of stability sets would be necessarily different from one which uses the Nash-property as a point of orientation.