The Philosophy of Science Association gives the Hempel Award for lifetime achievement every two years. The most recent recipient was Bas van Fraassen in 2012. This award was the impetus for this Festschrift in his honor.

Bas van Fraassen is a leader in the school of thought called anti-realism. There is nothing mystical about this descriptor. The anti-realism school of philosophy of science holds that it is impossible to provide the literal truth about the physical world. What we claim we know about the physical world consists of the models we use to represent the world. This approach is pragmatic and fundamentally optimistic in that finding the best representations and models to investigate is a continuing quest into deeper understanding despite the critical separation between models and the physical world. The physical world remains and provides a concrete correlation to the ways in which it is represented and modeled. The scientist and the philosopher of science accept this, but do not speak about this relationship with more certainty. Our mental constructs of the physical world are what we really know. Epistemology is introspective.

After a brief prologue, the book is divided into four parts, each with two or three chapters. Included among the chapters are two contributions by van Fraassen. The four parts are: (1) “Philosophical Coordinates,” in which the basic structure of van Fraassen’s concepts is laid out; (2) “Models and Representations,” covering both the basic theory in the first of van Fraassen’s contributions and a second chapter on representing evidence in a forensic context; (3) “Models and Reality,” which includes non-classical logic in van Fraassen’s system and a critical study of van Fraassen’s study of the work of Perrin on Brownian motion; and (4) “Scientific Explanation and Epistemic Values Judgments,” which discusses explanation as a pragmatic tool and contains van Fraassen’s second contribution on values, choices, and epistemic stances. Belief and understanding become the bases of choice and action.

All of the authors were either students of or close collaborators with van Fraassen. The contributions are supportive and appreciative of his ideas. The style of writing is approachable for a work in philosophy. It is worth noting how van Fraassen employs the history of science in his first essay. The history of science reveals the evolution of models and the means of representing them and the physical world. The history of science is inseparable from the philosophy of science and science itself.

Why should computer scientists care about this book? The issues raised are pertinent to several areas and applications in computing. Although van Fraassen’s ideas have not been extended from basic science to applied science and technology, doing so should be a realistic goal. Applied science and technology involve value choices, and van Fraassen’s ideas could be useful in developing a philosophy of applied science and technology. Computer code makes real the models and representations of the underlying reality when we simulate the behavior of an object or a system. We are building models to represent a system or object. We verify and validate models and simulations. How well do they contribute to understanding the object or the set of objects interacting together in a system? Are we really discovering the truth about physical reality or our own mental construct? We should reflect on these questions as we work.