Positioning Verfification in the Context of Software/System Certification

Formal verification applied to software has been seen as an important focus in research for determining the acceptability of that software for use. However, in examining the requirements for determining the safety of a software intensive system for use in critical situations, it is quite clear that verification plays a role,but not necessarily a central role. It is entirely possible that a piece of software satisfies its specification, but is unsafe to use. (The first and foremost reason for this is that the program satisfies an unsafe specification.) In this paper we will address the nature of certification in the context of critical systems, decomposing it,by means of a new philosophical framework, into four aspects: evidence, confidence, determination and certification. Our point of view is that establishing the safety (in a very general sense) of a system is a confidence building exercise much in the same vein as the scientific method; our framework serves as a setting in which we can properly understand and develop such an exercise. We will then place formal verification and assurance cases in this setting, discussing their roles and limitations.Keywords: Software certification, System certification, Formal specification, Verification,Critical systems, Safety, Assurance cases, Safety case

Proofs Versus Experiments: Wittgensteinian Themes Surrounding the Four-Color Theorem

The Four-Colour Theorem (4CT) proof, presented to the mathematical community in a pair of papers by Appel and Haken in the late 1970's, provoked a series of philosophical debates. Many conceptual points of these disputes still require some elucidation. After a brief presentation of the main ideas of Appel and Haken’s procedure for the proof and a reconstruction of Thomas Tymoczko’s argument for the novelty of 4CT’s proof, we shall formulate some questions regarding the connections between the points raised by Tymoczko and some Wittgensteinian topics in the philosophy of mathematics such as the importance of the surveyability as a criterion for distinguishing mathematical proofs from empirical experiments. Our aim is to show that the “characteristic Wittgensteinian invention” (Mühlhölzer 2006) – the strong distinction between proofs and experiments – can shed some light in the conceptual confusions surrounding the Four-Colour Theorem

Philosophy of Computer Science: An Introductory Course

There are many branches of philosophy called “the philosophy of X,” where X = disciplines ranging from history to physics. The philosophy of artificial intelligence has a long history, and there are many courses and texts with that title. Surprisingly, the philosophy of computer science is not nearly as well-developed. This article proposes topics that might constitute the philosophy of computer science and describes a course covering those topics, along with suggested readings and assignments

Computer theorem proving in math

We give an overview of issues surrounding computer-verified theorem proving in the standard pure-mathematical context. This is based on my talk at the PQR conference (Brussels, June 2003)

Real-time and Probabilistic Temporal Logics: An Overview

Over the last two decades, there has been an extensive study on logical formalisms for specifying and verifying real-time systems. Temporal logics have been an important research subject within this direction. Although numerous logics have been introduced for the formal specification of real-time and complex systems, an up to date comprehensive analysis of these logics does not exist in the literature. In this paper we analyse real-time and probabilistic temporal logics which have been widely used in this field. We extrapolate the notions of decidability, axiomatizability, expressiveness, model checking, etc. for each logic analysed. We also provide a comparison of features of the temporal logics discussed

The Logic of the Method of Agent-Based Simulation in the Social Sciences: Empirical and Intentional Adequacy of Computer Programs

The classical theory of computation does not represent an adequate model of reality for simulation in the social sciences. The aim of this paper is to construct a methodological perspective that is able to conciliate the formal and empirical logic of program verification in computer science, with the interpretative and multiparadigmatic logic of the social sciences. We attempt to evaluate whether social simulation implies an additional perspective about the way one can understand the concepts of program and computation. We demonstrate that the logic of social simulation implies at least two distinct types of program verifications that reflect an epistemological distinction in the kind of knowledge one can have about programs. Computer programs seem to possess a causal capability (Fetzer, 1999) and an intentional capability that scientific theories seem not to possess. This distinction is associated with two types of program verification, which we call empirical and intentional verification. We demonstrate, by this means, that computational phenomena are also intentional phenomena, and that such is particularly manifest in agent-based social simulation. Ascertaining the credibility of results in social simulation requires a focus on the identification of a new category of knowledge we can have about computer programs. This knowledge should be considered an outcome of an experimental exercise, albeit not empirical, acquired within a context of limited consensus. The perspective of intentional computation seems to be the only one possible to reflect the multiparadigmatic character of social science in terms of agent-based computational social science. We contribute, additionally, to the clarification of several questions that are found in the methodological perspectives of the discipline, such as the computational nature, the logic of program scalability, and the multiparadigmatic character of agent-based simulation in the social sciences.Computer and Social Sciences, Agent-Based Simulation, Intentional Computation, Program Verification, Intentional Verification, Scientific Knowledge

How the Conception of Knowledge Influences Our Educational Practices: Toward a Philosophical Understanding of Epistemology in Education

This paper explores how the conception and valuation of the knowledge within our educational practices determines the planning, writing, and implementation of the curriculum. There is a pressing need for educators to philosophically and systematically understand the relationship between the foundational epistemological beliefs that ground a curriculum and its relationship to forming the notions of competency, pedagogy, and the methods for evaluating and assessing student progress. These issues are not only relevant, but crucial when attempting to justify a particular conception of education, which relates directly to the student\u27s potential for intellectual growth and social development. It may be argued that the comprehensive theory of curriculum planning manifests the intersection of philosophical critique, social inquiry, and psychological theory, and the author believes that bringing philosophy, and a formal methodology, to bear on the problems of education represents an instance where philosophy might contribute in a direct manner to the active and ongoing process of current educational reform