“I’d like to … present an essential and overarching principle”, Ramchal offers, to help explain many things about the world, about G-d’s interactions with it, and about the whys and wherefores of wrong and injustice. And it’s this.
Despite the independence, autonomy, and personal impetus that each and every thing in the world expresses, it only exists, thrives, and acts thanks to wafts of Divine life-energy radiating toward it known as a Divine “emanation” .
The classic illustration of this phenomenon is the sort of unearthly influence that the constellations have been said to have on all below. Our sages alluded to it with the statement that “each and every blade of grass down below has a (specific) constellation in the heavens that swipes at it and says ‘Grow!'” (Breishit Rabbah 10:6). Rambam explicated the principle in his Guide for the Perplexed (2:10 and elsewhere) as did many others of our teachers .
The important thing to realize, though, is that the extent, variety, and duration of each emanation follows a series of Divine mechanisms specific to each moment, situation, and recipient that’s not at all easily read from the “outside”, except for those who “know the ordinances of the heavens, or (how they) fix their rule over the earth” (Job 38:33).
It’s because of this mechanism in fact that G-d is termed “the fountain of living waters” (Jeremiah 17:13) and “the source of life” (Psalms 36:10).
It’s important to realize, though, that given that G-d hasn’t a body, any emanation that comes from Him isn’t a part of His Being itself — any sort of direct handing-off of one thing or another from Him to us, if you will. Each emanation is a phenomenon that He created to do as He sees fit (see Guide for the Perplexed 2:12) .
In fact, nothing that has to do with this world emanates from His essential Being, which is far beyond this world, despite His interactions with us. Everything here, good and bad, is a phenomenon that He created to do what it has to. And it all follows rules that He set for it.
We, too, are phenomena that G-d created to do what we have to; and having that in common with the Divine emanations that animate and empower us connects us to them in a unique way.
Still the point remains that there are different shades of emanation, meant to serve different earthly needs. There are “intelligence emanations”, if you will, to animate intelligence, “strength emanations” to animate strength, and the like.
Should you wonder, though, why there just wouldn’t be a single all-encompassing emanation to serve all the needs of the world, that’s easy enough to explain. G-d does indeed emit what we might term a “composite” emanation — one single amorphous extension of His will, but we don’t experience it that way. It’s just that when it touches upon our own situation it takes on as particular hue and tone specific to the task at hand, whether it’s to allow for intelligence, strength or the like.
We’ll turn next to how this touches upon the various instances of wrong and injustice in the world.
 See 1:14:3 above and note 7 there for an explanation. While the citation there serves as a sort of comforting reminder that nothing is without its Divine sustenance, the point to be made later on is that even wrong and injustice are sustained by G-d’s emanation.
 Perhaps the simplest illustrations of the principle on a day-to-day level are our vital need for oxygen, food and drink; our psychological need for acceptance and love; our intellectual need for insight and instruction; and our spiritual need for connections to G-d either in prayer, Divine service, or Torah study . Doesn’t that all indicate something “out there” feeding and nourishing, or inspiring something “down here”?
 See Derech Hashem 1:5:2-3, 2:7:1-2; see R’ Shriki’s very important note 63 for other sources, as well as some references to Rambam’s perspective in contradistinction to Ramchal’s; and see R’ Goldblatt’s Kabbalistic references in his notes 9, 11 and 14 and on pp.478-479.
 Ramchal is citing Rambam’s point here to eventually clarify the idea that though G-d indeed fuels the emanations that would be necessary for all the instances of wrong and injustice in the universe, nevertheless that emanation isn’t directly from G-d or a part of His Being — it only serve a specific purpose. This underscores the point that while G-d certainly allows for wrong and injustice since things only exist and go on with His awareness and approval, still the point is that it’s separate from His essence and only serves a temporary end which will be undone in the end.
Rabbi Yaakov Feldman has translated and commented upon “The Gates of Repentance”, “The Path of the Just”, and “The Duties of the Heart” (Jason Aronson Publishers). His works are available in bookstores and in various locations on the Web.