  Aristotle describes the property that a triangle has angles equal to two right angles as being per se5 (= per se4) and universal, but also the property of ‘having internal angles equal to two right angles’ as per se accidens (kath’ hauto sembebêkôs) of triangle. It is commonly thought that these are somehow essential accidents. Since these follow from per se properties by necessity, it seems strange to call them accidents at all. Sometimes, however, it is more appropriate to think of accidents as concomitants, the result of different demonstrative chains. Alternatively, Aristotle frequently uses the same word to indicate consequences. In that case, they should be called per se consequences.