summary of The Epistemology of Groups by Jennifer Lackey:

Jennifer Lackey’s The Epistemology of Groups is a groundbreaking investigation into how groups—as opposed to individuals—can be considered knowers, agents of belief, and bearers of epistemic responsibility. Drawing on debates in social epistemology, Lackey challenges the tendency to treat group knowledge as merely reducible to the sum of individual members’ knowledge, arguing instead that groups often exhibit epistemic properties that cannot be explained solely at the individual level. She examines how group testimony, group belief, and group justification operate, showing that organizations, institutions, and collectives can generate and transmit knowledge in ways distinct from personal cognition. Central to her argument is the idea that groups can be epistemically blameworthy or praiseworthy for failures and successes in knowledge practices—such as when a jury delivers a verdict, a corporation issues a report, or a scientific community evaluates evidence. Lackey critiques both the “summativist” view (which sees group belief as the aggregation of individual beliefs) and overly strong collectivist accounts (which treat groups as if they have minds of their own), proposing instead a nuanced middle position where groups are epistemic agents constituted by, but not reducible to, the activities of their members. The book also considers pressing practical issues, such as misinformation, institutional bias, and the epistemic authority of scientific bodies, underscoring the real-world consequences of how we understand collective knowledge. In doing so, Lackey not only clarifies conceptual puzzles about group belief and responsibility but also provides a robust framework for addressing epistemic failures in public life. Ultimately, The Epistemology of Groups reveals how our most pressing challenges—climate change, public health, political polarization—depend on understanding and improving the epistemic practices of groups as much as individuals.