Masaharu Mizumoto

This work explores the conceptual and empirical issues of the concept of knowledge and its relation to the pattern of our belief change, from formal and experimental perspectives. Part I gives an analysis of knowledge (called Sustainability) that is formally represented and naturalistically plausible at the same time, which is claimed to be a synthesized view of knowledge, covering not only empirical knowledge, but also knowledge of future, practical knowledge, mathematical knowledge, knowledge of general facts. Part II tries to formalize the natural pattern of belief change assumed in Sustainability in terms of a specific formal theory of belief change, after carefully examining the notions of belief, belief change, and Information, from which the cognitive function F in Chapter 3 is actually constructed, which is later implemented by a computer program and its behavior against random input is demonstrated. In Part III we proceed to examine the analysis empirically. In particular, we will investigate Sustainability from the developmental point of view. We first justify experimental approach in philosophy as a legitimate method of philosophical investigation, and then developmental approach in particular. The specific proposal of experiment here is what we call the Gettier Task, an analogue of the famous false-belief task in developmental psychology, which has been much discussed in philosophy of mind. Two versions of the Gettier Task were tested on children aged from 6 to 12, and we claim that the data obtained empirically supports our analysis of knowledge, or Sustainability.

In this paper we introduce a paradigm of experiment which, we believe, is of interest both in psychology and philosophy. There the subject wears an HMD (head-mount display), and a camera is set up at the upper corner of the room, in which the subject is. As a result, the subject observes his own body through the HMD. We will mainly focus on the philosophical relevance of this experiment, especially to the thesis of so-called 'immunity to error through misidentification relative to the first-person pronoun'. We will argue that one experiment conducted in this setting, which we call the bodily illusion experiment, provides a counterexample to that thesis