Aksidente is die veranderlike eienskappe of kenmerke van ‘n substansie wat nie noodsaaklik vir daardie substansie se identiteit is nie. ‘n Mens se haarkleur, gewig of stemming is byvoorbeeld aksidente – hierdie eienskappe kan verander sonder dat die persoon ophou bestaan. Die substansie (die persoon) bly konstant, terwyl die aksidente wissel. Aksidente kan nie onafhanklik van ‘n substansie bestaan nie; hulle is altyd eienskappe van iets. Hierdie onderskeid tussen substansie en aksidente help ons verstaan hoe dinge kan verander en tog dieselfde bly, en speel ‘n belangrike rol in teologiese besprekings oor God se onveranderlikheid.
Accidents are the variable properties or characteristics of a substance that are not essential to that substance’s identity. A person’s hair colour, weight, or mood, for example, are accidents – these properties can change without the person ceasing to exist. The substance (the person) remains constant while the accidents vary. Accidents cannot exist independently of a substance; they are always properties of something. This distinction between substance and accidents helps us understand how things can change yet remain the same, and plays an important role in theological discussions about God’s immutability.