Computer science is a broad discipline. Theoretical computer science is very mathematical, whereas software development has all the hallmarks of an engineering activity. Further facets merge with psychology and cognitive science and applications are found throughout the physical sciences and engineering. The philosophy of computer is concerned with conceptual issues that arise by reflection upon the nature of computer science. The topics covered reflect the latter’s wide range: What kind of discipline is computer science? What are the roles of design and experimentation? What role is played by mathematics? What do correctness proofs establish? These are only a few of the questions that form the body of the philosophy of computer science. But here we shall not attempt to spell out a larger range of issues; instead we refer the reader to the more detailed conceptual overview in (Turner & Eden 2008).

This is a second collection of papers on the subject. The first, published in Mind and Machines (17:2, July 2007), contained papers that had their origin in the philosophy of computer science track of the Fourth European Computing and Philosophy conference
(ECAP 2006). This special edition of the Journal of Applied Logic consists of a collection of papers built upon papers given at the Fifth European Computing and Philosophy conference (ECAP 2007). In both cases, papers that enriched those presented at the conference were solicited.