Ibn Sina on Substances and Accidents

Erwin Tegtmeier


The Christian Metaphysicians of the Middle Ages, particularly Aquinas learnt a lot about Aristotle’s metaphysics from Islamic philosophers such as Ibn Sina (latinised as Avicenna). However, Ibn Sina (or Alfarabi) did not merely reproduce Aristotle but introduced far-reaching innovations to Aristotelian metaphysics. They deviated more from Aristotle than they were aware of since the Aristotle they knew was Neoplatonically dyed. Avicenna’s major innovation was the concept of existence which is lacking in Aristotle’s metaphysics. Therefore it is Ibn Sina who does ontology as Aristotle defined it, namely the science of being as being. Aristotle’s ontology is actually the science of the model being (ousia), and thus not ontology but ousiology. Because of the Neoplatonic influence Ibn Sina tended to essentialism which is then to be found also in Aquinas. Both countenance universals in a certain way and both draw on the concept of existence to distinguish substances and accidents. However, Aquinas returns with respect to the nature of a substance to a certain extent to Aristotle.


20th century philosophy; metaphysics; philosophy; Wittgenstein Ludwig; accident; composition; individuation; Aristotle; Thomas of Aquin; prime matter; substance

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