Why do some physical systems possess consciousness, while others do not? We view consciousness not as a subjective experience, but rather as a physical event accompanying experience. Is this a question of physics? Or is it a question of the theory of causation? Physics and the theory of causation serve different descriptive purposes. To describe a causal model, we introduce an asymmetric relation between cause and effect that is necessary for describing causality, but not physical laws. We propose that the generation of consciousness is determined by a system's internal causal mechanisms, rather than by a system's functions (i.e., physically determined input-output relations). To explain these intrinsic causes, we focus on whole-to-parts causality. Traditionally, whole-to-parts causality is considered an emergent phenomenon rather than a mechanism. We devise a method for explicitly implementing these mechanisms in a causal model by examining how causes originating at higher levels are transmitted to lower levels within a system. We then propose a dual-laws model (DLM), which features distinct dynamical laws at higher and lower levels. Finally, we discuss the generation of functional consciousness and its causality based on the DLM.