claim: "[Models] are full of fudge factors that are fitted to the existing climate, so the models more or less agree with the observed data.
evidence: A good theory: Is elegant (Formal elegance; no ad hoc modifications) Contains few arbitrary or adjustable elements (simplicity/parsimony) Agrees with and explains all existing observations (unificatory/explanatory power) Makes detailed predictions about future observations that can disprove or falsify the model if they are not borne out.