This article deals with complex systems. It takes the reader on a journey to the origins of the paradigm shift which has taken place in the sciences since the path breaking works of Edward N. Lorenz, Benoît B. Mandelbrot, Mitchell J. Feigenbaum, and others. Gradually, linear “twodimensional” thinking has been replaced by non-linear “multi-dimensional” reasoning and multi-factorial genesis, risk, and uncertainty have come into focus. The article looks at the beginnings of the conception of complex systems — chaos theory — and reveals the implications for the law and legal science. Having explained the premises of chaos theory by means of a metaphor (the kneading of dough) the article proposes to look at the law through the lens of chaos: the law, especially case law, is perceived as a system which is itself subject to the phenomenon of chaos. The power of the image of chaos is illustrated by means of a study of the case law of the European Court of Justice on family reunification of moving persons and its projection to Switzerland in an attempt to create parallel regimes. The article also takes advantage of chaos theory to portray the broader implications for society and the law, tentatively illustrating them by thoughts on the Lisbon judgment of the German Federal Constitutional Court of 30 June 2009 and on UN Security Council Resolution 1244 of 10 June 1999 (on Kosovo).