SIMPLE MODELS FOR COMPLEX SYSTEMS – TOYS OR TOOLS?
Wroclaw University of Science and TechnologyThe talk is thought of as a personal journey through the wonderful world of simple models designed to describe complex systems. I am not going to make a review, neither talk about the most important models. Instead I will present models and papers that influenced my scientific work, brought me new ideas or surprised me. My talk will be divided into three parts. In the first part I will present simple models of biological evolution and population dynamics. Among them the seminal Bak-Seppen model, particularly important from my perspective. In the second part I will talk about interactions between physics and social sciences. I will start from the history of sociology and “social physics”, next introduce several simple models of societies. I will try to answer the question whether they should be regarded as tools or as toys. Finally, in the last part, I will address the question: Can people be treated as particles? I will present several social experiments and show how the results of these experiments were used to build a simple model of opinion dynamics, known as the Sznajd model. See also:
 P. Bak, K. Sneppen. Punctuated equilibrium and criticality in a simple model of evolution. Phys. Rev. Lett. 71 (1993) 4083-4086.
 M.E.J. Newman, R.G. Palmer. Models of Extinction. A Review. arXiv:adap-org/9908002v1.
 Ph. Ball. The physical modeling of society: a historical perspective. J. Phys. A, 314 (2002) 1–14.
 C. Castellano, S. Fortunato, V. Loreto. Statistical physics of social dynamics. Rev. Mod. Phys. 81 (2009).