The program of intervening, manipulating, constructing and creating is central to natural and engineering sciences. A renewed wave of interest in this program has emerged within the recent practices and discourse of nano-technoscience. However, it is striking that, framed from the perspective of well-established epistemologies, the constructed technoscientific objects and engineered things remain invisible. Their ontological and epistemological status is unclear. The purpose of the present paper is to support present-day approaches to techno-objects ( ontology ) insofar as they make (...) these hidden objects epistemologically perceivable. To accomplish this goal, it is inspiring to look back to the origin of the project of modernity and to its founding father: Francis Bacon. The thesis is that everything we need today for an adequate (dialectic-materialist), ontologically well-informed epistemology of technoscience can be found in the works of Bacon—this position will be called epistemological real-constructivism. Rather than describing it as realist or constructivist, empiricist or rationalist, Bacon’s position can best be understood as real-constructivist since it challenges modern dichotomies, including the dichotomy between epistemology and ontology. Such real-constructive turn might serve to promote the acknowledgement that natural and engineering sciences, in particular recent technosciences, are creating and producing the world we live in. Reflection upon the contemporary relevance of Bacon is intended as a contribution to the expanding and critical discussion on nano-technoscience. (shrink)