Legal formalism is both a descriptive theory and a normative theory of how judges should decide cases. In its descriptive sense, formalists believe that judges reach their decisions by applying uncontroversial principles to the facts. Although the numerous decided cases imply numerous principles, formalists believe that there is an underlying logic to these principles that is straightforward and which legal experts can readily discover. The ultimate goal of formalism would be to formalise the underlying principles in a single and determinate system that could be applied mechanically (hence the label 'mechanical jurisprudence'). Formalism has been called 'the official theory of judging'. It is the thesis to which legal realism is the antithesis.