Mika Oksanen

In this article I go through the history of the notion of a multiverse, and compare how it has been used in non-fiction (in philosophy and natural science), and in science fiction. Within non-fiction I discuss, among others, modal realism and theories of branching space-time in metaphysics, and within natural science, the many worlds interpretation of quantum mechanics and the theories of cosmic inflation and braneworlds. In fiction I look (among other subjects) at Victorian precursors of the notion of multiverse, Michael Moorcock’s multiverse, super-hero multiverses, and utopias and dystopias that make use of a multiverse. I also discuss the danger of nihilism raised by many versions of a theory of a multiverse. I also examine and critique, in the light of philosophy and natural science, the feasibility of some common tropes of this type of narrative—like that of a person meeting duplicates or counterparts when traveling through the multiverse.

In this article I want to investigate the concept of reliability employed in process reliabilist theories of justification and knowledge. What is essential to process reliabilist theories of justification is that there is a sense of the word ”justifi- cation” (a strong or an objective concept of justification) such that a belief is justified only if it is produced by a reliable process. Different versions of reliabilism may add different sufficient conditions to this to get a complete definition of justification or knowledge, and disagree about whether there are other interesting concepts of justification, but all agree that reliability (global or local) is necessary for both justification (in some sense) and knowlede. This of course, raises the question of what reliability is. Reliabilist theories of justification cannot be said to have a very secure foundation if they do not address this question. However, reliabilists have not done very much to answer it as has of course been often pointed out by their opponents. The most famous reliabilist, Alvin Goldman, has in one place [6, page 63] suggested that the concept of reliability he uses should be understood so that reliability is a propensity; however, he does not formulate this idea very exactly nor develop it very far. However, I think that his suggestion is correct, and important; in this article I will try to clarify it by linking it to formal analyses of propensities that are found in the literature (as well as the whole discussion about interpretations of probability) and explore its consequences