Enneads III.1: Concerning Fate
Stoic and Epicurean Causeless Origin Really the Utmost Determinism
Now among the things that become, or among those that although perpetually existent do not always result in the same actions, it may be boldly asserted that everything has a cause. We should not admit (the Stoic contention[99]) that something happens without a cause, nor accept the (Epicurean[100]) arbitrary convergence of the atoms, nor believe that any body initiates a movement suddenly and without determining reason, nor suppose (with Epicurus again[101]) that the soul undertakes some action by a blind impulse, without any motive. Thus to suppose that a thing does not belong to itself, that it could be carried away by involuntary movements, and act without motive, would be to subject it to the most crushing determinism. The will must be excited, or the desire awakened by some interior or exterior stimulus. No determination (is possible) without motive.
EVERY GOOD THING HAS SOME CAUSE; NATURE BEING THE ULTIMATE CAUSE.
If everything that happens has a cause, it is possible to discover such fact's proximate causes, and to them refer this fact. People go downtown, for example, to see a person, or collect a bill. In all cases it is a matter of choice, followed by decision, and the determination to carry it out. There are, indeed, certain facts usually derived from the arts; as for instance the re-establishment of health may be referred to medicine and the physician. Again, when a man has become rich, this is due to his finding some treasure, or receiving some donation, to working, or exercising some lucrative profession. The birth of a child depends on its father, and the concourse of exterior circumstances, which, by the concatenation of causes and effects, favored his procreation; for example, right food, or even a still more distant cause, the fertility of the mother, or, still more generally, of nature (or, in general, it is usual to assign natural causes).