This contribution is a gentle introduction to so-called dynamic epistemic logics, that can describe how agents change their knowledge and beliefs. We start with a concise introduction to epistemic logic, through the example of one, two and finally three players holding cards; and, mainly for the purpose of motivating the dynamics, we also very summarily introduce the concepts of general and common knowledge. We then pay ample attention to the logic of public announcements, wherein agents change their knowledge as the (...) result of public announcements. One crucial topic in that setting is that of unsuccessful updates: formulas that become false when announced. The Moore-sentences that were already extensively discussed at the conception of epistemic logic in Hintikka’s ‘Knowledge and Belief ’ (1962) give rise to such unsuccessful updates. After that, we present a few examples of more complex epistemic updates. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:BOOK REVIEWS 97 supposed by actual idealism is above all moral and involves what Gentile describes as an aspect of divinity or infinity,as well as a concrete, historical aspect. The following chapter treats of the philosophy of "actual" idealism and compares the views of Kant and Gentile on relations between moral conscience and freedom. According to Yalentini, Gentile's idealism is essentially an ethical view. This chapter concludes with noting (...) that Gentile 's solution to the problem of historical knowledge differs profoundly from that of Hegel and Croce. For "reason" is not, for Gentile, a particular interpretation of historical process, but is rather the "reason" of consciousness in activity. In Chapter In, Valentini discusses Gentile's views on art and religion. The section on art concludes with a comparison between Gentile on feeling and Kant on the transcendental unity of apperception. Whereas art is supposed to be one abstract moment of spirit, religion is the other abstract moment. Valentini suggests that Gentile and Feuerbach hold similar religious views on the attributes of divinity, which are nothing other than the loftiest qualities which man feels to possess in his essence. The history of religion is then the history of the progressive humanization of God. Gentile's religion represents a sort of modem Catholicism in that it understands revelation as a fact of conscience, church as a historical institution, dogma as having a negative character and God as a member of the dialogue between God and man. Moreover, Gentile's Catholicism has a national character; it is the religion of the Italian people. Chapter Iv treats of the relations between individual and state. For, according to Gentile, an individual is inconceivableapart from the social relations which lie within him. Here Valentini distinguishes in detail the differences and similarities between the views of Hegel and Gentile on the relations between state and individual. The differences between the views of these two philosophers are due to the differences between their methods. The method of Hegel is empirical and historical, and examines the state (which remains historical) from an external point of view. According to an idealistic method, however, thought is not to be the spectator of a process, but in every instance, an actor, and philosophizing does not result from an analysis of historical reality, but from the negation of this reality in the name of an ideal, which philosophy is to draw from it (reality). The Appendix includes a critical evaluation of the theory of the dialectic. Here Valentini hopes to distinguish between the imaginary and the real or historical applications of the dialectic. He begins his evaluation by asking: Does the doctrine of the dialectic, like the philosophy of idealism, possess negative connotations, which cannot be separated from it? Valentini suggests that in order to answer this question, we must determine the extent to which the dialectical scheme is constitutive of every concept or truth in general. For this is the way in which Hegel intended that the dialectic be understood and evaluated. Some views in Hegel's philosophy of nature are then criticized according to empirical criteria. In conclusion, Valentini attempts to answer both "internal" and "external" criticisms of Marx's view of the dialectic, and shows that there are problems involved in its application, which still have to be resolved. Mv~ M. MILBURN 9 ~an Jos~ ~ate College Husserl und Kant: eine Untersuchung ~ber Husserls Verh~iltni~ zu Kant und zum Neubantianismus. By Iso Kern. (The Hague : Martinus Nijhoff, 1964.Pp. xxiii q- 448.) This is a very important book. In fact, it is indispensable for a study of Husserl and is, at the same time, almost as valuable for a study of Kant, for it deals with the kind of searching questions that must be asked when one deals with transcendental idealism in any one of its forms. But two reasons in particular, make this book significant. One is the fact that Iso Kern was able to make extensive use of hitherto unpublished materials (manuscripts, lecture notes, letters, etc.), available only in the Husserl Archives and here quoted for the first time--and 98 HISTORY OF PHILOSOPHY quoted in great numbers. The other is Kern's philosophical competence... (shrink)

The present authors have given a mathematical model of Mach's principle and of the Mach–Einstein doctrine about the complete induction of the inertial masses by the gravitation of the universe. The analytical formulation of the Mach–Einstein doctrine is based on Riemann's generalization of the Lagrangian analytical mechanics (with a generalization of the Galilean transformation) on Mach's definition of the inertial mass and on Einstein's principle of equivalence. All local and cosmological effects—which are postulated as consequences of Mach's principle by C. (...) Neumann, Mach, Friedländer and Einstein—result from the Riemannian dynamics with the Mach–Einstein doctrine. In celestial mechanics it follows, in addition, Einstein's formula for the perihelion motion. In cosmology, the Riemannian mechanics yields two models of an evolutionary universe with the expansion lows R ~ t or R ~ t2. In this paper, secular consequences of the Mach–Einstein doctrine are examined concerning palaeogeophysics and celestial mechanics. The research predicted secular decrease of the Earth's flattening and secular acceleration of the motion of the Moon and of the planets. The numerical values of this secular effect agree very well with the empirical facts. In all cases, the secular variation $\dot{\alpha}$ of the parameter α is the order of magnitude $\dot{\alpha}=-H_0 \alpha$ , where H0 is the instantaneous value of the Hubble constant: $H_0 =\left({\dot{R}/R} \right)_0 \approx \left( {0.5-1.0} \right) \times 10^{-10}a^{-1}$ . The relation of the secular consequences of the Mach–Einstein doctrine to those of Dirac's hypothesis on the expanding Earth, and to Darwin's theory of tidal friction are also discussed. (shrink)

Contemporary correspondence is invoked to provide further information concerning the decision of the Cavendish Society to publish an English translation of Gmelin's Handbuch der Chemie in 1846, and the opposition this provoked.

The question I want to discuss is that of the sense and respects in which morality is strictly a matter for the individual. To hear some people talk you would think that it is wholly so. Not only do I have to make my own moral decisions; I have in a way to make them on my own terms, in so far as the rules I take to govern my actions are rules I have freely accepted, or at the least (...) not positively repudiated. In law I can be bound by statutes which I regard as abhorrent or even of whose content I am ignorant ; that a similar situation should obtain in morals is commonly treated as absurd. If I see nothing wrong with a certain practice, such as premarital sex or drug-taking, I can’t be brought morally to book for indulging in it. Morals is not solely a matter of personal taste, for the nature of moral judgment is such that the moral agent legislates not just for himself but for all who are similarly situated; equally, however, it is not something which can be externally enforced. There are no objective moral principles, plain for all to see, against which to measure moral error, and though there is fairly widespread agreement among the respectable that some forms of conduct are morally admirable and others morally deplorable, we are under no obligation to respect these “conventions.” A man’s only true obligation here is to follow his conscience and thus do what he takes to be right, in the light of the best information about the situation he can get. (shrink)

This paper presents an empirical test of Schlegel's “interaction interpretation” of the theory of special relativity. Analysis of the UTC time scales maintained at various observatory sites over the world indicates that neither Schlegel's “interaction interpretation” of the theory of relativity nor the conventional “space-time coordinate transformation interpretation” of relativity can significantly improve agreement between the UTC time scales. Instead evidence for the effects of accelerations on clock rates is suggested.