Designing and making games is complex, chaotic and difficult, and the relationship between design and the game development process is not well understood. The myth of predictive design control and fallacies of misplaced concreteness have confused understandings of game design, both in theory and practice. To resolve these problems, I use Dewey’s theory of inquiry, both as a method of philosophical investigation and as a way of understanding the process of game development. I also use experience-focused philosophies, embodied theories of meaning, tacit knowing and theories of design to examine the characteristics of games, game experiences and game design. These theories are used to identify important constituents in the game design situation, and to address the mix of formal, aesthetic and creative elements that defines game design. In doing so, I rely on my experience as a game designer along with analysis of several game development projects, to investigate the nature of indeterminacy and design coherence in the game development process. This thesis shows that game design is a complex process that inherently involves at least 40 sources of indeterminacy. It also shows that the formal aspects of a game co-develop with the skilled performance of integrative design work in a social design situation. In this project-specific collaborative learning process, the meaning of design concepts can easily be disrupted in the solving of problems and coordination of different discourses. The co- development process allows designers to expand their rational capacity while coping with emergent complexity (of both games and their making).