Kant further elaborates on the distinction between "analytic" and "synthetic" judgments. A proposition is analytic if the content of the "predicate-concept" of the proposition is already contained within the "subject-concept" of that proposition. For example, Kant considers the proposition "All bodies are extended" analytic, since the predicate-concept ('extended') is already contained within—or "thought in"—the subject-concept of the sentence ('body'). The distinctive character of analytic judgements was therefore that they can be known to be true simply by an analysis of the concepts contained in them; they are true by definition. In synthetic propositions, on the other hand, the predicate-concept is not already contained within the subject-concept. For example, Kant considers the proposition "All bodies are heavy" synthetic, since the concept 'body' does not already contain within it the concept 'weight'. Synthetic judgments therefore add something to a concept, whereas analytic judgments only explain what is already contained in the concept.