Prologue

1. As the Philosopher says in Ethics, 10, the ultimate happiness of man consists in the best operation of man, which is of the highest power, that is to say, the power of the intellect, with respect to the best intelligible.

2. Since the effect is known through the cause, it is clear that the cause according to its own nature is more intelligible than the effect, even if at sometime with respect to us the effects be more known than the causes, because they arise out of particulars, falling under the senses, we have received cognition of universal and intelligible causes.

3. It is therefore proper that, simply speaking, the first causes of things be according to themselves the most intelligible and the best intelligible, because they are beings to the greatest degree and true to the greatest degree, as is clear from the Philosopher in Metaphysics, 2, although these sorts of first causes are less known, and later known, with respect to us.

4. Our intellect relates itself to them just like the eye of the owl with respect to the sun, which it cannot perceive perfectly on account of its exceeding clarity.

5. It is proper therefore that the ultimate happiness, which can be had in this life, consist in the consideration of first causes, because that little bit which can be known about them is more worthy of love and more noble than all those which can be known about inferior things, as is clear from the Philosopher in On the Parts of Animals, 1.

6. Since this cognition is perfected in us after this life, man can be made perfectly happy according to what the Evangelist says, this is life eternal so that they may know you, the true living God (John 17:3).

7. And from this is what the intention of the philosophers principally was in this matter that through all things which they considered in things they might arrive at cognition of the first causes. Whence they set up the study about first causes last, in the consideration of which they set aside the last time of their own life.

8. First, beginning from logic which hands down the method of the sciences.

Second, proceeding to mathematics, of which even children can be capable.

Third, to natural philosophy, which needs time because it requires trial.

Fourth, to moral philosophy, a suitable hearer of which cannot be a young man.

Finally, they stop at the divine science, which considers the first causes of beings.

9. Therefore certain things written about first principles, distinguished into diverse propositions, have been found, as if through a mode of those considering some individual truths. And in Greek it is found thus: the Book of Proclus the Platonist Containing 211 Propositions, which is entitled, Elements of Theology. But in Arabic this book is found which is called De causis among the Latins, which is agreed to be translated from the Arabic and not to be had any more in Greek. From this it seems that it was excerpted by some one of the Arab philosophers out of the aforesaid book of Proclus, especially because everything that is contained in the latter book is contained in a much fuller and more detailed way in the former.

10. Therefore the intention of this book, which is called the De causis, is to make a determination about the first causes of things; and because the name of the cause imports a certain order and the order is found in causes with relation to themselves he premises as if a certain principle for the whole following work, a certain proposition pertaining to the order of causes, which is thus: