Simplicity may proxy for more fundamental principles (parsimony, fewer ontological commitments), making it rationally relevant even when theories are observationally equivalent now.

?Rate how convincing each reason is below to see the overall strength.

No one has weighed in yet. Be the first to share reasons for or against this statement.

Ontology(Carnap argues this enterprise is based on a mistake): The philosophical discipline that tries to answer hard questions about what there really is.
Proxy(syntactic structure serves as a proxy for provenance and justification): Something you use as a stand-in or substitute to measure or represent something else that's harder to observe directly.
Rationally relevant(as used in epistemology): Something that gives us a good logical reason to prefer one idea over another, even if the evidence doesn't force us to.
observationally equivalent(Applied to systems of equations (1)–(2) and (1)–(3) which share the same solutions in measured variables X, Y, Z): Two systems are observationally equivalent when they imply or represent exactly the same facts about the patterns of correlations that obtain among the measured variables.

Based on where you are in your exploration