Rationality in Social Science: Introduction -- From Pascal to Ellsberg: Paradoxes of Rationality Stimulate the Progress of Decision Theory -- Rationology, Rationality and Reason -- "Das Modell ist dafür nicht geeignet!" ("The Model is not Suitable for This!"): The Model of Frame Selection and a Corrective Replication of the Findings in the Fehr-Gächter Experiments on the Development of Cooperation in Public Good Situations -- Sociology in Times of Pandemic: Metatheoretical Considerations and the Example of the Covid-19 Crisis -- When Do People Follow the Behavior of Others? The Effects of Descriptive and Injunctive Norms, and the Werther Effect -- Revenge and Gratitude in Trust-Based Encounters. Experimental Evidence on Process-Based Reciprocity -- How More Severe Punishment Generates Less Norm Enforcement. Further Evidence of Paradoxical Effects of Norm Enforcement in Inspection Games -- Balancedness. Emerson's theory in the Upanishads, in Cooperative Game Theory, and beyond -- Endogenizing Conditions for Cooperation of Rational Egoists -- Opposing Effects of Objective and Subjective Social Status on Prosociality: Theory and Quasi-Experiment -- Green Homeowners? An Empirical Application of Fischel's Homevoter Hypothesis -- How can Employers Signal Trustworthiness to Job Seekers? Determinants of Employer Reputation.