There are three degrees in the spiritual world, and three degrees in the natural world, hitherto unknown, according to which all influx takes place.
It is discovered, by the investigation of causes from effects, that there are degrees of two kinds, one in which are things prior and posterior, and another in which are things greater and less. The degrees which distinguish things prior and posterior are to be called degrees of altitude, and also discrete degrees; but the degrees by which things greater and less are distinguished from each other are to be called, degrees of latitude, and also continuous degrees.
 Degrees of altitude, or discrete degrees, are like the generations and compositions of one thing from another; as, for example, of any nerve from its fibers, and of any fiber from its fibrils; or of any piece of wood, stone, or metal from its parts, and of any part from its particles. But degrees of latitude or continuous degrees are like the increments and decrements of the same degree of altitude as to breadth, length, height, and depth; as of greater and smaller volumes of water, or air, or ether; and as of large and small masses of wood, stone, or metal.  All and each of the things in both worlds, the spiritual and the natural, are, from creation, in degrees of both these kinds. The whole animal kingdom in this world is in those degrees both in general and in particular; and the whole vegetable kingdom and the whole mineral kingdom likewise; as also is the expanse of atmospheres from the sun even to the earth.  There are therefore three atmospheres discretely distinct according to the degrees of altitude, both in the spiritual world and in the natural world, because each world has its sun; but the atmospheres of the spiritual world, by virtue of their origin, are substantial, and the atmospheres of the natural world, by virtue of their origin, are material. And because the atmospheres descend from their origins according to those degrees, and are the containants, and, as it were, the carriers of light and heat, it follows that there are three degrees of light and heat. And because light in the spiritual world in its essence is wisdom, and heat there in its essence is love, as was shown above in its own article, it follows also that there are three degrees of wisdom and three degrees of love, hence three degrees of life; for they are graded by those things through which they pass.  Hence it is that there are three angelic heavens: a highest, which is also called the third heaven, where are the angels of the highest degree; a middle, which is also called the second heaven, where are the angels of the middle degree; and a lowest, which is also called the first heaven, where are the angels of the lowest degree. Those heavens are also distinguished according to the degrees of wisdom and love. Those who are in the lowest heaven are in the love of knowing truths and goods; those who are in the middle heaven are in the love of understanding them; and those who are in the highest heaven are in the love of being wise, that is, of living according to those things which they know and understand.  Since the angelic heavens are distinguished into three degrees, therefore the human mind is also distinguished into three degrees, because the human mind is an image of heaven, that is, it is a heaven in the least form. Hence it is that man can become an angel of one of those three heavens, and this is effected according to his reception of wisdom and love from the Lord: an angel of the lowest heaven if he receives only the love of knowing truths and goods; an angel of the middle heaven if he receives the love of understanding them; and an angel of the highest heaven if he receives the love of being wise, that is, of living according to them. That the human mind is distinguished into three regions, according to the three heavens, may be seen in the Relation inserted in the work on Conjugial Love (n. 270). From these things it is evident that all spiritual influx to man and into man descends from the Lord through these three degrees, and that it is received by man according to the degree of wisdom and love in which he is.  The knowledge of these degrees is of the greatest use at the present day; since many, because they do not know them, subsist and inhere in the lowest degree, in which are the senses of their body, and from ignorance, which is intellectual thick darkness, cannot be elevated into spiritual light, which is above them. Hence naturalism invades them, as it were spontaneously, as soon as they enter on any investigation and inquiry concerning the human soul and mind, and its rationality, and still more if they inquire concerning heaven and the life after death. Thus they become comparatively like those who stand in the marketplaces with telescopes in their hands, looking at the sky, and utter vain predictions; and also like those who chatter and also reason concerning every object they see, and everything they hear, without there being in it anything rational from the understanding. But such persons are like butchers, who believe themselves to be skilled in anatomy, because they have examined the viscera of oxen and sheep outwardly but not inwardly.  But it is a truth, that to think from the influx of natural light, not enlightened by the influx of spiritual light, is nothing else than dreaming, and to speak from such thought is to talk nonsense. But more concerning these degrees may be seen in the work on The Divine Love and The Divine Wisdom (n. 173-281).