This paper is the first of a series of three which attempt to integrate categories of description aimed at characterizing the experience of learning in terms of the logical relationships that exist between them. The description of the qualitatively different ways in which various aspects of reality are experienced and conceptualized, and the search for logical relations between the categories of description arrived at have been labelled phenomenography. The categories dealt with here depict characteristics of the outcome and style of learning, and the approach to and the motivation for learning. It is concluded that a "horizontalised" outcome (in which a text's hierarchical structure is levelled out) implies operation learning in terms of Pask's dichotomy of styles, of which comprehension learning represents the other alternative. Comprehension learning implies a deep approach (as it is defined by Marton) while its opposite, the surface approach, implies extrinsic motivation. In such a way, categories of description can be linked to each other very much as a Wittgensteinian family resemblance structure: no thread runs through the whole rope, but it is still the same rope all the way. (Author/PN)