I begin my discussion of a subject of cognition in the philosophy of Kazimierz Ajdukiewicz by recounting his view of science. In his paper "Methodology and Metascience' he distinguishes three different meanings of the word' science'. First,' science' means all kinds of activities undertaken by scientists. Second,' science' is a set of sentences which are the result of these activities. Science as an activity is a phenomenon which takes place in time and even in space. It has its history. But, science as a result of these activities, as a set of sentences uttered by scientists, has its history as well. Its components change over time. Here the development of science depends on the empirical data collected by scientists and the language they have invented. Thus, science as a result of research is a time construct as well.