Tacit knowing as a concept and legitimate topic of scholarship came up in philosophical research in the second half of the 20th century in the form of some influential works by Michael Polanyi (although similar concepts had been discussed before). Systematic epistemological studies on the topic are still scarce, however. In this article, I support the thesis that tacit knowing pervades all our common major divisions of knowledge and that it therefore must not be neglected in epistemological research. By this (...) approach I am simultaneously giving a systematic back-up for Polanyi's claim that the tacit component is found in all knowledge. (shrink)