ABSTRACT
This chapter deals with the kinds of knowledge and their properties and the important theme of the integration of different kinds of knowledge. Vincenti's categorisation is that some of the knowledge of engineers is indeed derived from scientific research but another important part of it comes from the direct experience of technological reality. By referring to GLARE's development one can see, how many different kinds of knowledge were necessary not only to produce a material with the right properties but also to apply that material in the design of a plane. The three examples of normativity are knowledge of requirements, knowledge of functions and knowledge of good practice. The most striking fact is that, natural sciences only contributes to two kinds of knowledge, namely to theoretical aids and to quantitative data. The word tacit, used for the first time in the context by Polanyi in The Tacit Dimension, means that knowledge is implicitly present without being articulated or written down.
