WHAT DOES IT MEAN FOR SOMETHING TO BE SIMPLE? Simplicity, Economy, and Differentiation

A scientific account can become more economical without establishing that its physical subject lacks the features left unrepresented. An orbital calculation may omit Earth's mountains and internal structure while preserving the gravitational relation needed to predict its motion. A theory may also derive distinct regularities from shared principles without eliminating their differences. Such achievements concern what an account must represent or posit independently; their success does not by itself determine the constitution of what is described.Differentiated Realism proposes that something is simple under a specified respect insofar as no differentiation obtains under that respect. The judgment requires identifying what receives the attribution and the characteristic or relation being investigated. Comparative fewness, ease of understanding, and theoretical economy do not by themselves establish an absence of differentiation. Mathematical invariance, physical constitution, and existential dependence admit different simplicity judgments, each with its own conditions of justification.An absence must be established through grounds appropriate to the subject and respect: demonstration for a mathematical relation, calibrated investigation for physical differentiation, or a defensible metaphysical argument for existential dependence. The resulting attribution extends only to what those grounds establish. Differences omitted from an account, undetected by an instrument, or excluded through an argument must not be treated as the same kind of absence. AI-assisted tools were used for language editing, including grammar, clarity, and stylistic consistency. The author retains full responsibility for the arguments, interpretations, and final text.