Einstein began the relativistic cosmology by his 1917 paper. But what is his most important contribution to the cosmology? I will argue that the answer is that he changed the notion of gravity so as to imply both the attractive and the repulsive force. Beginning with the elements of the general relativity, I will briefly review de Sitter's objection against Einstein's spherical universe, Lemaitre's and Eddington's works, the classic version of the expanding universe, the big-bang cosmology, and the inflationary cosmology. The seminal ideas emerged from the Einstein-de Sitter controversy culminated in the fruitful results of the inflationary cosmology, and the key idea was the gravity as a repulsive force.
Whereas Einstein's theory claims that non-Euclidean geometry should hold in the presence of a strong gravitational field, "the bending of a light path" is meaningful only when we presuppose the classical Euclidean space. This situation shows that there is a kind of measurement problem of general relativity. The present author discusses this problem and underscores the point that the revolutionary character of general relativity consists in its prediction of some phenomena which can be observed but cannot be explained without ad hoc hypothesis in terms of classical standpoints concerning space-time. Furthermore, the present author analyses the concept of 4-dimensional neighborhood of relativity physics. We must drastically change the classical concept of neighborhood of space and time. The objectively valid definition of the neighbourhood of an event is the 4-dimensional space-time region of |ds|<ε, and neither of |dt|<ε nor of |dl|<ε. The so-called light cone (|ds|=0) acquires an intuitive meaning of the realm of presentational immediacy as a three dimensional space with a temporal depth.
In his book, The Concept of Logical Consequence, Etchemendy claims that the currently standard model-theoretic account of logical consequence is "the interpretational semantics" and does not capture logicality. The purpose of this paper is to defend the model-theoretic account from Etchemendy's criticisms. Through comparison with Sher's "Tarskian logic" and her model-theoretic definition of logical constants, I aim to demonstrate that the basis of Etchemendy's arguments are mistaken. I then explain that the model-theoretic account of logical consequence guarantees its logicality by the semantic functions of logical constants.
We can extract some information from a wrong testimony. There have been some systems of propositional modal logic called logic of beleaf and knowledge, and they explain this extraction. On the other hand, predicate logic for wrong testimony has not been studied enough. This work proposes a logical system of predicate modal logic which explains such extraction. Especially, our logical system explains the extraction from a testimony which involves misidentification of individuals.
As was noted by Frege, the criteria of identity for abstract objects of certain sorts can be formulated in the following form: f(x) = f(y) iffφ(x, y). I argue that the criterion of identity for persons can be formulated in the same form, and that reference to persons hinges on a conceptual operation analogous to the characterization of a function f by the formulation of such a criterion. This account suggests that a certain puzzle about personal identity over time has no determinate answer, owing to the semantic indeterminacy in the singular terms in terms of which the puzzle is posed. I present a semantic solution to the puzzle along these lines, within the framework of supervaluation semantics.
This paper deals with Evans' view on demonstrative thoughts, i.e., thoughts typically expressed using demonstratives such as 'this' or 'that.' As is well known, Evans defends against (so-called) the Direct Reference Theory the claim that singular terms have Fregean Senses, while contending that demonstrative thoughts (expressed using these terms) are object-dependent. Criticisms have been given to this two-sided contention of Evans', but they have not paid due attention to his subtle and detailed theory of demonstrative identification. In this paper I examine, through scrutinizing this theory of demonstrative identification, whether Evans' defense of his two-sided contention above is successful or not. I will conclude by arguing that it is not successful at least in establishing the object-dependency of demonstrative thoughts.