time, location, situation (or position), action, and passion ("being acted on"). Together with "substance", these nine kinds of accidents constitute the ten fundamental categories of Aristotle's ontology. Catholic theologians such as Thomas Aquinas have employed the Aristotelian concepts of substance and accident in articulating the theology of the Eucharist, particularly the transubstantiation of bread and wine into body and blood. According to this tradition, the accidents (or species) of the appearance of bread and wine do not change, but the substance changes from bread and wine to the Body and Blood of Christ. Modern philosophy In modern philosophy, an accident (or accidental property) is the union of two concepts: property and contingency. In relation to the first, an accidental property (Greek symbebekos) is at its most basic level a property. The color "yellow", "high value", "Atomic Number 79" are all properties, and are therefore candidates for being accidental. On the other hand, "gold", "platinum", and "electrum" are not properties, and are therefore not classified as accidents. There are two opposed philosophical positions that also impact the meaning of this term: Anti-essentialism (associated with Willard Van Orman Quine) argues that there are no essential properties at all, and therefore every property is an accident. Modal necessitarianism (associated with Saul Kripke), argues for the veracity of the modal system "Triv" (If P is true, then P must be true). The consequence of this theory is that all properties are essential (and no property is an accident). See also Energeia Essence Hypostasis (philosophy and religion) Indeterminism Modal logic Ousia Qualia Randomness Coincidence and synchronicity, in which accident may seem (to human cognition) to defy mere randomness alone (although whether it truly does is a philosophical challenge) Romance copula § Spanish: ser versus estar Stochastics Substance theory References Concepts in logic Concepts in metaphysics Philosophy of Aristotle