For myself, however according to my weak judgment, the matter appears to stand thus: that these three opinions are partly to be accepted as true, and partly to be rejected as false;— accepted as true, because men speak after the appearances which they see, and also because these men see how things come upon them as if accidentally; to be set aside as fallacious, because the wisdom of God is too profound for them— that wisdom which founded the world, and created man, and ordained Governors, and gave to all things the degree of pre-eminence which is suited to every one of them. What I mean is, that this power is possessed by God, and the Angels, and the Potentates, and the Governors, and the Elements, and men, and animals; but that this power has not been given to all these orders of beings of which I have spoken in respect to everything (for He that has power over everything is One); but over some things they have power, and over some things they have not power, as I have been saying: in order that in those things over which they have power the goodness of God may be seen, and in those over which they have no power they may know that they have a Superior.
There is, then, such a thing as Fate, as the astrologers say. That everything, moreover, is not under the control of our will, is apparent from this— that the majority of men have had the will to be rich, and to exercise dominion over their fellows, and to be healthy in their bodies, and to have things in subjection to them as they please; but that wealth is not found except with a few, nor dominion except with one here and another there, nor health of body with all men; and that even those who are rich do not have complete possession of their riches, nor do those who are in power have things in subjection to them as they wish, but that sometimes things are disobedient to them as they do not wish; and that at one time the rich are rich as they desire, and at another time they become poor as they do not desire; and that those who are thoroughly poor have dwellings such as they do not wish, and pass their lives in the world as they do not like, and covet many things which only flee from them. Many have children, and do not rear them; others rear them, and do not retain possession of them; others retain possession of them, and they become a disgrace and a sorrow to their parents. Some are rich, as they wish, and are afflicted with ill-health, as they do not wish; others are blessed with good health, as they wish, and afflicted with poverty, as they do not wish. There are those who have in abundance the things they wish for, and but few of those things for which they do not wish; and there are others who have in abundance the things they do not wish for, and but few of those for which they do wish.
And so the matter is found to stand thus: that wealth, and honours, and health, and sickness, and children, and all the other various objects of desire, are placed under the control of Fate, and are not in our own power; but that, on the contrary, while we are pleased and delighted with such things as are in accordance with our wishes, towards such as we do not wish for we are drawn by force; and, from those things which happen to us when we are not pleased, it is evident that those things also with which we are pleased do not happen to us because we desire them; but that things happen as they do happen, and with some of them we are pleased, and with others not.
And thus we men are found to be governed by Nature all alike, and by Fate variously, and by our freedom each as he chooses.
But let us now proceed to show with respect to Fate that it has not power over everything. Clearly not: because that which is called Fate is itself nothing more than a certain order of procession, which has been given to the Potentates and Elements by God; and, in conformity with this said procession and order, intelligences undergo change when they descend to be with the soul, and souls undergo change when they descend to be with bodies; and this order, under the name of Fate and γένεσις, is the agent of the changes that take place in this assemblage of parts of which man consists, which is being sifted and purified for the benefit of whatsoever by the grace of God and by goodness has been benefited, and is being and will continue to be benefited until the close of all things.
The body, then, is governed by Nature, the soul also sharing in its experiences and sensations; and the body is neither hindered nor helped by Fate in the several acts it performs. For a man does not become a father before the age of fifteen, nor does a woman become a mother before the age of thirteen. In like manner, too, there is a law for old age: for women then become incapable of bearing, and men cease to possess the natural power of begetting children; while other animals, which are likewise governed by their nature, do, even before those ages I have mentioned, not only produce offspring, but also become too old to do so, just as the bodies of men also, when they are grown old, cease to propagate: nor is Fate able to give them offspring at a time when the body has not the natural power to give them. Neither, again, is Fate able to preserve the body of man in life without meat and drink; nor yet, even when it has meat and drink, to grant it exemption from death: for these and many other things belong exclusively to Nature.
But, when the times and methods of Nature have had their full scope, then does Fate come and make its appearance among them, and produce effects of various kinds: at one time helping Nature and augmenting its power, and at another crippling and baffling it. Thus, from Nature comes the growth and perfecting of the body; but apart from Nature, that is by Fate, come diseases and blemishes in the body. From Nature comes the union of male and female, and the unalloyed happiness of them both; but from Fate comes hatred and the dissolution of the union, and, moreover, all that impurity and lasciviousness which by reason of the natural propensity to intercourse men practise in their lust. From Nature comes birth and children; and from Fate, that sometimes the children are deformed, and sometimes are cast away, and sometimes die before their time. From Nature comes a supply of nourishment sufficient for the bodies of all creatures; and from Fate comes the want of sustenance, and consequent suffering in those bodies; and so, again, from the same Fate comes gluttony and unnecessary luxury. Nature ordains that the aged shall be judges for the young, and the wise for the foolish, and that the strong shall be set over the weak, and the brave over the timid; but Fate brings it to pass that striplings are set over the aged, and the foolish over the wise, and that in time of war the weak command the strong, and the timid the brave.
You must distinctly understand that, in all cases in which Nature is disturbed from its direct course, its disturbance comes by reason of Fate; and this happens because the Chiefs and Governors, with whom rests that agency of change which is called Nativity, are opposed to one another. Some of them, which are called Dexter, are those which help Nature, and add to its predominance, whenever the procession is favourable to them, and they stand in those regions of the zodiac which are in the ascendant, in their own portions. Those, on the contrary, which are called Sinister are evil, and whenever they in their turn are in possession of the ascendant they act in opposition to Nature; and not on men only do they inflict harm, but at times on animals also, and trees, and fruits, and the produce of the year, and fountains of water, and, in short, on everything that is comprised within Nature, which is under their government.
Source: The Book of the Laws of Various Countries (New Advent)