Vaclav Rajlich

In the classical account of knowledge, S knows that P if and only if S believes that P, S is justified in believing that P, and P is true (JTB).. In 1963, Gettier presented two problems that casted doubt on this account. Since then, numerous authors proposed modifications or clarifications of JTB, however, these efforts have not produced a satis-factory solution. In this paper, the focus is on logical properties of justification. The Get-tier problem Case II is expressed in sentential logic and Gettier Minimal Assumption (GMA) is introduced. It is shown that Gettier must have used GMA or some other as-sumption that entails GMA in his construction of Case II. Rejection of GMA solves Get-tier problem Case II and it is a step towards a better understanding of the logical proper-ties of justification and knowledge.

Program comprehension is an essential part of software engineering. The paper describes the constructivist theory of comprehension, a process based on assimilation and accommodation of knowledge. Assimilation means that the new facts are either added to the existing knowledge or rejected. Accommodation means that the existing knowledge is reorganized in order to absorb new facts. These processes are illustrated by case studies of knowledge-level reengineering of a legacy program and of incremental change. In both cases, we constructed preliminary knowledge from the program documentation, and then adjusted it by comprehending the actual code. The case studies supported constructivism as a suitable theory of program comprehension.