Immanuel Kant’s natural philosophy attracts rather little attention today. If at all subject to scrutiny, what comes into focus is almost never his natural philosophy as a whole but only certain parts. Among philosophers, while Kant’s epistemological and moral writings are still lively discussed, his natural philosophical or scientific writings are all but neglected. Only Kant’s effort to establish the metaphysical foundations of mechanics is now and then addressed by philosophers of science. Among historians of science, his hypothesis about the origin of our planet system or his as-if-teleological concept of organicity arouse occasional interest since these pieces of his natural philosophy are taken to be original and presentiments or even beginnings of later scientific achievements. Usually, however, Kant’s scientific work is regarded as uninteresting, i.e., as either amateurish or unoriginal.

However, if one conceives of history of science as something other than a narrative of a success story, focusing on the heroes of the triumphal march of science, a different image of Kant’s scientific work emerges. It then appears as an extremely illuminating mirror image of the sciences of his age. Kant kept always in touch with the sciences. Being obliged, from the mid 1750s on, to lecture about the whole range of scientific subject matters at the university of Königsberg, he had to keep pace with scientific developments and was familiar with contemporary scientific knowledge, at least as it was rendered in textbooks. In some fields, however, he was even able to bring forth his own ideas – ideas, which a historically trained eye has to regard as being on an equal footing with the ideas of the famous scientists of his age.

Kant’s natural philosophy mirrors the fractured nature of the scientific knowledge of his age as well as the attempt to integrate this knowledge. His efforts are in no way inferior to those of famous contemporaries and deserve attention. Closer investigations of them promise discoveries of significance for history of science in general as well as for a better understanding of Kant as a scientist.