This thesis analyzes the direction of time problem in the framework of philosophy of science. The radiation arrow, Newtonian arrow, thermodynamic arrow and quantum mechanical arrow have been studied in detail. The importance of the structure of space-time concerning direction of time is emphasized.

The main purpose of the present study is to show that scientific realism is still worth advocating despite its vulnerability in the face of anti-realist objections. For, it does not seem possible to &lsquo / do science&rsquo / without realist commitments. The second purpose of this study is to investigate the plausibility of the novel versions of realism in the sense that whether they can satisfactorily respond to the anti-realist objections. Regarding the main purpose, I try to show that theoretical terms are neither reducible to observables nor they can be dispensed with. Hence in scientific theories there always remains a metaphysical part. Regarding the second purpose I discuss ontic structural realism which holds the individualistic attributions responsible for the metaphysical parts in theories and suggests that non-individualistic interpretation of theoretical terms is possible. The legitimacy of Ontic structural realism&rsquo / s suggestion, as its advocates claim, lies within quantum facts.

In this thesis, I analyze the classical tripartite definition of knowledge. According to this definition there are three conditions for a knowledge claim to arise, namely, belief, truth and justification conditions. The main problem with this definition is even if these three conditions are satisfied one may not know a proposition p because of the fact that the justification of the proposition p may not be relevant in showing that p is true. Therefore, my primary purpose is to establish a strong conceptual connection between justification and truth conditions. To realize this, first, I defend a three-way interrelation between these three conditions. Second, I inquire as to which kind of justification should lead us to which kind of truth. To answer to this question, I postulate three kinds of realities, namely, Subjective Reality, Inter-Subjective Reality, and Allegedly Pure Reality. Furthermore, I re-define the justification condition in such way that there is a kind of whole justification and it requires both internal and external justification. According to this conception of reality and re-definition of justification there already exists a strong conceptual connection between internal justification and Subjective Reality which is completely subject-relative. And I defend the existence of such a connection also between the whole justification and Inter-Subjective Reality. Finally, I argue that no conception of justification can lead us to an Allegedly Pure Reality that the hardest version of skepticism claims to exist.

The dissertation aims to set out a methodological framework conducive to further research into the demarcation problem of logical constants through a critical examination of the principal proposals for the problem. Logical constants should be characterised so as the essential values of logic, i.e., necessity, normativity and formality, are secured. Formality is central to the proposed framework in consideration of its relation to validity / necessity and normativity are established with reference to formality. Logical constanthood is analysed into logicality and constanthood to explore the conditions and constraints on logical form. On the purpose of their determination, a Wittgensteinian stance is endorsed, focusing on the view of language as a reflexive autonomous realm. The autonomy of language unfolds a specific viewpoint that indicates that logical form is existentially grounded in the possibilities presented by the autonomy. v Gentzen&rsquo / s natural deduction and sequent calculi are adopted as the proper perspectives to discuss the relations of logicality and constanthood to formalisation. Logical constants are required to be fixed so that the resultant logical form is sterile of content and semantically inert with respect to argument content. In addition to the conditions of harmony in logical form, mutual disharmony is introduced. Analytic and grammatical truths are specified as constraints to logical form. In particular, the conservativeness condition is found to be irrelevant to logical form. The framework incorporates methodological pluralism as a probe into the understanding of logicality. The dissertation suggests a bidimensional programme of research related to formal conditions and the Wittgensteinian grammatical constraints.

This thesis aims to make an analysis of the concepts of &amp / #8216 / existence&amp / #8217 / . It also constructs four new definitions based on the concept of &amp / #8216 / effect&amp / #8217 / for different concepts of beings. By reasoning based on these definitions and some pre-suppositions, a foundation for an axiomatic system of ontology is tried to construct.

In this thesis I study the problem of logical constants with respect to logical truth and logical consequence. In order to do that, I focused on the following two questions. First, what is a logical constant and what kind of relation there is between a logical truth, logical consequence and logical constant? Second, what are the solutions to the problem and to what extent these criteria can solve it? The main argument of my thesis is to determine that all of the examined systems are satisfactory to considerable level still none of these is completely acceptable.

The main objective of this study is to shed light on some difficulties involved in the formulation of the problem of contingency in Leibniz&rsquo / s philosophical system. Leibniz&rsquo / s mature philosophy is characterized by the solutions he proposes for this problem, and the ontological ideas underlying or assisting them. &lsquo / The problem of contingency&rsquo / refers to the tension between his conceptual containment theory of truth and his claim that true existential propositions &ndash / that is, propositions which concern actual individuals &ndash / are all contingent. Though Leibniz does not seem to have one definite theory of contingency, two general lines of thought can nevertheless be discerned from his fragments on propositions and propositional truth. The first one is the infinite analysis theory, which is regarded in general as Leibniz&rsquo / s real theory of contingency, and the other is a theory of necessity, providing a division between absolute and hypothetical modalities. This thesis is not a study on the question whether Leibniz did really manage to solve the problem, but rather an attempt to trace the problem to its logical and ontological origins, and redefine it under a relatively simple form. It is first shown that Leibniz&rsquo / s theory of propositions relies heavily on his ontological conception of modalities, which covers the idea of a division between pure possibility and actuality / and then this idea is shown to be reflected on the logical level as a division between essential and existential truths. Finally it is argued that the two lines of thought and some peculiar characteristics of Leibniz&rsquo / s conception of modalities bring us to the conclusion that his real problem is the (deliberate) inability of his propositional calculus to express the difference between truths of reason (essential truths) and truths of fact (existential truths) as a logical structural one.

The purpose of this dissertation is to search the primitives of Axiomatic Set Theory in Leibnizian Philolosophy, nourishing, roughly, from Platonic idea of universal-particular distinction, Aristotelian syllogistic propositions of Organon-Categoria and Euclidean Methodology in Elements. The main focus of the dissertation intends to examine the analyticity of Leibnizian Metaphysics and the anologies between the subject-predicate relation in The Philosophy of Leibniz and Axiomatic Method in general and Set Theory in particular. In doing this, special emphasis will be ascribed to the notion of sets as to universality and/or nullness of a class, probable causes of paradoxes and in this context a critical analysis of Russell Paradox.

Indiscernibility, interchangeability and resemblance relations may be named as weak-identity relations or identity-like relations. Indeed,identical objects can be thought to satisfy all these three relations. According to realist view, these relations are defined on the basis of properties of objects. While indiscernibility is a context-independent relation, since indiscernibility is defined in terms of all properties of objects, interchangeability and resemblance relations are defined in terms of some significant properties of objects and thus they should be regarded as context-dependent. We should consider the following points while comparing rivalling theories of resemblance: 1. The theory explaining resemblance relations between objects should cover as many domains as possible. Instead of simply admitting that objects of a given type may resemble each other, the theory should explain how these relations are possible. 2. Objects do not just resemble or they do not / resemblance is a relation that admits degrees. Thus the theory providing a finer analysis of close and weak resemblances should be preferred. In comparison to resemblance nominalism, realist theory of resemblance is strongerwith respect to both points. The criticism that realist view may not explain degrees of resemblance can be rejoined by removing the indeterminacy as to the nature of this notion.Among knowledge representation systems, property and attribute systems provide a simple but strong models for analytic ontology. Weak identity relations can easily be defined in these systems and the results following from these definitions can be seen to conform to our intuitions about weak identity relations.