Philosophy lacks criteria to evaluate its philosophical theories. To fill this gap, this essay introduces nine criteria to compare worldviews, classified in three broad categories: objective criteria (objective consistency, scientificity, scope), subjective criteria (subjective consistency, personal utility, emotionality), and intersubjective criteria (intersubjective consistency, collective utility, narrativity). The essay first defines what a worldview is and exposes the heuristic used in the quest for criteria. After describing each criterion individually, it shows what happens when each of them is violated. From the (...) criteria, it derives assessment tests to compare and improve different worldviews. These include the is-ought, ought-act, and is-act first-order tests; the critical and dialectical second-order tests; the mixed-questions and first-second-order third-order tests; and the we-I, we-it, and it-I tests. The essay then applies these criteria and tests to a concrete example, comparing the Flying Spaghetti Monster deity with Intelligent Design. For another application, it draws more general fruitful suggestions for the dialogue between science and religion. (shrink)