Philosophical Viewpoints vs Tier Structure

Atomic theory is often presented as a linear progression toward increasingly accurate representations of physical reality. This paper offers an alternative analysis, examining atomic models in terms of model admissibility rather than cumulative truth. Scientific frameworks are assessed according to the empirical and conceptual conditions under which they generate stable, predictive explanations, and the points at which they break down when applied beyond those limits. Tracing the progression from early atomism through classical, quantum, and modern field-based descriptions, the paper argues that model failure typically reflects boundary crossing rather than falsity. Later models do not invalidate earlier ones absolutely, but clarify the constraints that define their domains of applicability. The analysis is methodologically conservative, makes no new physical or ontological claims, and is fully compatible with established scientific theories.