Natural selection explains why organisms exist and why phylogenetically important events induce specific activities in organisms. A framework that incorporates induction, time allocation among activities, and covariance between activities and environmental events provides a theoretical framework to account for a great range of behavioral phenomena. A few general equations define this multiscale molar view, which affords specific accounts of rate of a single activity—operant or non-operant—choice between two or more activities, performance on interval and ratio schedules, avoidance and punishment, and more. This chapter lays out the basic framework and shows its application to this variety of phenomena.