Abstract
Norms explained as grounds of practical judgment, using example of queue. Some norms informal, inexact, depend on common understanding ; some articulated in context of two-tier normative order: `rules', explicit or implicit. Logical structure of rules displayed. Informal and formal normative order explained, `institutional facts ' depend on acts and events interpreted in the light of normative order. Practical force of rules differentiated; either `absolute application' or `strict application' or `discretionary application', depending on second-tier empowerment. Discretion can be guided by values, principles standards. Pervasiveness of institutions and institutional facts, especially but not only in relation to institutions of state-law, including constitution and state-institutions. Searle's and Ruiter's theories of institution, institutional fact, considered: `constitutive rule' rejected in favour of `underlying principle', structure of `institutive, consequential and terminative' rules explained and defended. Ruiter's conception of `institutional `régime' considered and adopted, validity of norms and normative `régimes' considered and differentiated from truth of statements of institutional fact