In the early 1960s, American philosopher of science Thomas Kuhn contributed to a “crisis of rationality” with his hypothesis that science develops by means of paradigm shifts. He challenged the positivist concept of cumulative and continuous scientific progress. According to Kuhn, the relation between two succeeding scientific traditions ‘separated by a scientific revolution’ is characterized by conceptual incommensurability that constrains the interpretation of science as a cumulative, steadily progressing enterprise. Thomas Kuhn’s philosophy was heavily criticized by German-American biologist Ernst Mayr (...) as unapplicable to the history of biology. Mayr, one of the most outstanding evolutionary biologists of the 20th century and a “co-architect” of the so-called Modern Synthesis (contemporary Darwinism), published extensively on the history and philosophy of biology as he thought that theoretical biology cannot progress without proper philosophy of science. Being convinced of the progressive development of Darwinism, Mayr pointed out that Kuhn’s concept of scientific revolutions does not reflect conceptual changes in evolutionary biology. Here we summarize Mayr’s critiques of Kuhn and, based on our own research, take Mayr’s side in the controversy between two great thinkers. (shrink)

Ernst Haeckel formulated his biogenetic law, famously stating that ontogeny recapitulates phylogeny, in 1872. The Russian evolutionist Alexei Sewertzoff, and the Swiss-born zoologist Adolf Naef were among those who revised Haeckel’s law, thus changing the course of evolutionary theory and of developmental biology. Although Sewertzoff and Naef approached the problem in a similar way and formulated similar hypotheses at a purely descriptive level, their theoretical viewpoints were crucially different. While Sewertzoff laid the foundations for a Darwinian evolutionary morphology and is (...) regarded as a forerunner of the modern synthesis, Naef was one of the most important figures in “idealistic morphology”, which is usually seen as a type of anti-Darwinism. Both Naef and Sewertzoff aimed to revise Haeckel’s biogenetic law and came to comparable conclusions at the empirical level. This paper is an attempt to explain how their fundamentally different theoretical backgrounds influenced their views on the relationship between ontogeny and phylogeny. (shrink)