Modelling as a way of organising knowledge

The paper is motivated by the need to address anew the old topic of operational research and hard (but also soft) systems science: what is the role of mathematical modelling, how does it relate to knowledge, to creativity, to human concerns? Such a need arises because of the great change observed today, of informational revolution, of transition towards knowledge-based economy, towards networked organization of our social and economic life. During the last 50 years' operational research, mathematical modelling and computerised techniques of model analysis and optimisation contributed essentially to the change of perception of contemporary world, characteristic for the current informational revolution indicating the change of civilisation eras. These contributions have been noted during these years inside operational research, but analysed mostly from so-called soft systems thinking perspective. Main contributions to the actual formation of the new era, however, came from the hard systems research, in particular, as we shall show, from mathematical modelling in applications to the development of technological systems.