imposed upon me during his lifetime and I had pledged myself to him and to the circle to carry it out.
I judged that in the case of treatises which, like these, had been issued without consideration of logical sequence it was best to disregard the time-order.
Apollodorus, the Athenian, edited in ten volumes the collected works of Epicharmus, the comedy writer; Andronicus, the Peripatetic, classified the works of Aristotle and of Theophrastus according to subject, bringing together the discussions of related topics: I have adopted a similar plan.
I had fifty-four treatises before me: I divided them into six sets of nine, an arrangement which pleased me by the happy combination of the perfect number six with the nines: to each such ennead I assigned matter of one general nature, leading off with the themes presenting the least difficulty.
The First Ennead, on this method, contains the treatises of a more ethical tendency:—
1. On the Animate and the Man.
2. On the Virtues.
3. On Dialectic.
4. On Happiness.
5. Whether Happiness depends on Extension of Time.
6. On Beauty.
7. On the Primal Good and Secondary forms of Good.
8. On Evil.
9. On the Reasoned Withdrawal from Life.
The Second Ennead, following the more strictly ethical First, is physical, containing the disquisitions on the world and all that belongs to the world:—
1. On the World.
2. On the Circular Movement.
3. On the Stars.
4. On the Two Orders of Matter.
