It is difficult to "picture" knowledge if it indeed lacks form as this conception suggests. Yet a simple cartographic illustration of how knowledge exists without specific form should clarify the situation. ¥e may know where certain places are, or how certain areas are arranged, even though we have not actually seen them and have only derived such knowledge from maps. Yet if we were asked to escribe the graphic characteristics of the maps from which we derived the knowledge, it is unlikely that we would be able to recall line weights, type styles, or colors. Yet we know the relations that were depicted, regardless of the form of the original marks. Once we assimilated those marks and converted them into tacit knowledge, they lost their form. However, we can retain the relations of interest to us, that is, the structures of the maps from which they were obtained.
Barbara Petchenik,Cognition in Cartography, Newberry Library
