Abstract
This paper aims at extending the notion of thing knowledge put forth by Davis Baird. His Thing Knowledge (Baird 2004) proposes that scientific instruments constitute scientific knowledge and that to conceive scientific instruments as such brings about a new and better understanding of scientific development. By insisting on what “truth does for us,” Baird shows that the functional properties of truth are shared by the common scientific instrument. The traditional definition of knowledge as justified true belief would only apply to scientific instrumentation if we were to reject the subjective (and intentional) aspect of it, viz. belief. In consequence, Baird insists that scientific instruments can be seen only as a kind of objective knowledge, that is knowledge maintained by the scientific community but not individually by a given scientist. In this paper, I will argue for a conception of subjective thing knowledge according to which some scientific instruments (especially material models) can be understood as justified true beliefs. By combining Davis Baird’s thing knowledge and Clark and Chalmers’ hypothesis of extended cognition, I will show that it is possible to derive an analysis of material models as cognitive augmentation of the scientist's mind, and that such scientific instruments are to be understood as a material form of subjective knowledge, i.e. as external-to-the-brain justified true beliefs