Ideal Observer Theory
Aesthetics
Ideal Observer Theories in Aesthetics by Stephanie Ross.
Epistemology
Ideal Agents and Ideal Observers in Epistemology by Linda Zagzebski.
Ethics
Ethical Absolutism and the Ideal Observer by Roderick Firth, The Definition of an 'Ideal Observer' Theory in Ethics by Richard B. Brandt and The Artificial Moral Advisor: The 'Ideal Observer' Meets Artificial Intelligence by Alberto Giubilini and Julian Savulescu.
Law
The Reasonable Person by Alan D. Miller and Ronen Perry and The Empirical Reasonable Person by Christopher B. Jaeger.
History
The Mind of the Historian by Bruce Kuklick, Narrative and History by Alun Munslow and Narrative Factuality: A Handbook edited by Monika Fludernik and Marie-Laure Ryan.
Consensus
Consensus and the Ideal Observer by Keith Lehrer and Rational Consensus in Science and Society: A Philosophical and Mathematical Study by Keith Lehrer and Carl Wagner.