Final answer:
A theory is externally consistent when it aligns with observed data and existing theories, explains a wide variety of observations, and stands up to scientific inquiry and verification within its own conceptual framework. It is a robust explanation for observed phenomena that has been extensively supported by scientific evidence.
Step-by-step explanation:
The concept of a theory being externally consistent refers to its coherence and its ability to account for the data it aims to explain. In science, a theory is a well-developed set of ideas that proposes an explanation for observed phenomena and has been supported by extensive scientific evidence and verification. A theory must not only be compatible with existing observations and experimental data, such as the manner in which VSEPR theory predicts molecular shapes, but it should also align with other current theories, proposing a parsimonious and unfussy explanation that can withhold high scientific standards and eventually gain acceptance within the scientific community.
A true theory, as accepted by the scientific community, is one that functions within its own conceptual framework. It must explain a wide variety of observations, including those previously unexplained, generate testable expectations, and be supported by independent verification, even though all observations are infused with theoretical perspectives. In summary, for a theory to be considered externally consistent, it must be thoroughly established within the context of the natural universe, be it in physics, chemistry, biology, or another domain of science.