are known not according to their own nature, but according to the character of the knowing subject.

A summary of Proclus's Elements of Theology circulated under the name Liber de Causis (Book of Causes). This book is of uncertain origin, but circulated in the Arabic world as a work of Aristotle, and was translated into Latin as such. It had great authority because of its supposed Aristotelian origin, and it was only when Proclus's Elements were translated into Latin that Thomas Aquinas realised