This article revisits the left-wing response to sociobiology in the 1970s and 1980s by examining the sociobiology debate in Finland in a larger European context. It argues that the Finnish academic left’s response to sociobiology represents a “third way” alongside the purely negative, often Marxist denial of biology’s relevance, which characterized the left’s response to sociobiology in many European countries such as Hungary and Sweden, and alongside the disregard that sociobiology confronted in most parts of Eastern Europe, as well as (...) in Germany. In the context of the last great political conflict of the Cold War in Europe, the controversy over the American “Euromissiles” in 1979–1983, the Finnish academic left challenged the allegedly fatalistic sociobiological aggression and war theories with an alternative biological language, turning the increasing enthusiasm over evolutionary ideas into a pacifist cause. Using leftist and pacifist forums to inform citizens and politicians of such biologically evolved human characteristics as mutual care and sociability, the Finnish critics of sociobiology wished to boost the public spirit, and to rationalize the pacifist ideal of the European-wide popular movement against nuclear weapons and militarism. As a result, the academic leftists in Finland revived the early twentieth-century tradition of “peace biology.” A proper understanding of this development calls for an analysis that acknowledges Finland’s special geopolitical and cultural position in the Cold War world between East and West. (shrink)