<p>This study investigates the concept of <i>theory</i>, a notion central to understanding the nature and structure of scientific knowledge. In school science, theory is often introduced simply as the counterpart of experiment—its explanatory partner—and is used to account for laws, models, and problem-solving procedures. Yet the concept itself frequently lacks a clearly articulated identity, internal structure, or hierarchy of components. In contrast, the philosophy of science treats fundamental theories as the constitutive elements from which scientific knowledge is built. This role becomes especially salient when scientific disciplines are examined holistically, as in the development of modern physics alongside classical physics. By tracing the origins of scientific theory, we arrive at a definition aligned with the constitutional view of science as “the theory of the real.” This perspective supports a refined account of theory and motivates revisions to the commonly cited characteristics of science. We argue that the <i>Discipline–Culture paradigm</i> offers a productive representation of physics theory and examine its implications for the organization of physics curricula. Within this framework, the science taught and learned at schools appears as an epistemological family of fundamental theories that <i>coexist</i> rather than replace one another over time. We illustrate this approach through examples of teaching–learning materials, curricular structures, and summary lectures, and we briefly describe classroom implementations that tested this paradigm in physics education. The holistic perspective advanced here—emphasizing the hierarchical and interdependent structure of scientific theories—offers clear benefits for fostering public scientific literacy, which is largely shaped in school. In this view, science emerges as a <i>theatre of theories</i>, each illuminating the world through its own coherent vision.</p>