Recent work across art, biology and process ontology (Anderson, Dupré and Wakefield, 2019) has begun to build a visual epistemology of processes by bringing the practice of drawing, as a pathway to process thinking, back into the laboratory. In this talk, I join forces with this emergent literature, and extend it in what I take to be a compatible philosophical direction. I frame drawing as a pragmatist visual epistemology in its own right: a mode of inquiry, performed with pencil or pen on paper, in which one formulates visual hypotheses and experiments with the possible consequences of adopting certain ideas or conceptions, or with the consequences of seeing phenomena in a certain way. I develop this framework from the philosophical writings (and the accompanying drawings!) of the scientist, philosopher, and founder of Pragmatism Charles S. Peirce – himself a compulsive doodler and enthusiastic advocate of diagrammatic representations. Building on Peirce’s work, in the second part of this chapter I present three ways in which drawing can be framed as a kind of visual inquiry and as a pragmatist visual epistemology: delineating, reconfiguring and structuring. I illustrate each of these three visual modes with concrete case studies of drawing in action, in concrete scientific contexts.