Philosophical foundations for Participatory Design are based on emerging trends in computer-based system designs that seek to go beyond the limits of formalization. These new trends represent efforts to restructure the design of computer-based systems in favor of newer approaches thats encourage creative thinking and doing design as participatory work between users and designers.

The general sense is that formalized descriptions while doing well to insure reliability and efficiency of a product cannot do much in the way of guaranteeing suitability and relevance in practical use.

The main distinction seems to be the difference between propositional knowledge and practical understanding. Propositional knowledge is that which one can come to know and describe in so many words. Factual information and what one can provide a definition for are good examples of propositional knowledge.

Practical understanding goes beyond formal description. It is understanding that comes from the practical experience of doing something and the recall to mind of earlier experiences (Ehn,1993). Propositional knowledge alone of how to draw does not make one a graphic artist, rather it is through practical understanding gained from experience in drawing that one can come to be a graphic artist. Useful designs rely on practical understanding of how tools are used. Designers gain little or no practical understanding from formal system descriptions. The feeling is that it is the lack of practical understanding of tools used by users that causes a hindrance to successful designs.

The goal of participatory design is to provide a context for design experts where they can gain the practical understanding they need for successful design. Users possess the needed practical understanding but lack the insight designers have into new technical possibilities. Bringing designers and users together is the first step towards the goal. The main difficulty lies in getting users to express their practical understanding in the context of new technological possibilities. Design by doing methods, prototyping, scenarios, and mockups are often used to suggest future possibilities to users. Users learn about possibilities and constraints of new computer tools, and as they put their skill into practice in the new environment, users teach designers their practical understanding.

Design takes on a new meaning in participatory design as the interaction between practical understanding and creation (Ehn, 1993). Users and designers use design artifacts as triggers for the imagination rather than as mirror images of reality. Relaxation from correctness of system descriptions opens an invitation to creativity and gives both users and designers a chance to see new aspects of an already well-known practice. It challenges both users and designers to either build on tradition or create something totally new.

Effectiveness of participatory design depends on the full participation of both users and designers. It remains a challenge in participatory design to provide an environment that encourages learning, creativity and communication between users and designers.