This book challenges traditional epistemological frameworks by developing a de-idealized account of epistemic systems that centers on knowledge practices rather than abstract principles alone. It develops an epistemic agent-based account of epistemic systems that incorporates the social, political, and ontological dimensions of knowledge production.

The book addresses critical gaps in current epistemological theory by examining how real-world knowledge practices unfold across different communities. Through a detailed case study of knowledge about testosterone across medical practitioners, trans masculine and non-binary users, and bodybuilding/entertainment sports communities, the book reveals how social organization, power dynamics, and ontological commitments shape epistemic systems. By integrating insights from the sociology of scientific knowledge, feminist political epistemology, and political ontology, the book offers fresh perspectives on fundamental epistemic questions, including: How do we understand disagreement between different knowledge communities? When should knowledge producers outside institutionalized science be recognized as experts? And what are the implications for science in a "post-truth" environment?

Epistemic Systems in Action will appeal to researchers and graduate students interested in epistemology, feminist philosophy, philosophy of science, social and political philosophy, gender studies, and the sociology of knowledge.

Sophie Juliane Veigl is a senior lecturer in philosophy of science and technology at the department of Philosophy, University of Vienna. She works at the intersection of philosophy of science, feminist philosophy, and epistemology. She is the co-editor of Methods in Philosophy of Science - A user's guide.