angels there are called spiritual-natural and celestial-natural.{1} Those who receive influx from the middle or second heaven, which is the spiritual heaven, are called spiritual-natural; and those who receive influx from the third or inmost heaven, which is the celestial heaven, are called celestial-natural.  The spiritual-natural angels and the celestial-natural angels are distinct from each other; nevertheless they constitute one heaven, because they are in one degree.

{Footnote 1} There are three heavens, inmost, middle, and outmost, or third, second, and first (n. 684 9594, 10270).  Goods therein also follow in triple order (n. 4938, 4939, 9992, 10005, 10017).  The good of the inmost or third heaven is called celestial, the good of the middle or second is called spiritual, and the good of the outmost or first, spiritual-natural (n. 4279, 4286, 4938, 4939, 9992, 10005, 10017, 10068).

32.  In each heaven there is an internal and an external; those in the internal are called there internal angels, while those in the external are called external angels.  The internal and the external in the heavens, or in each heaven, hold the same relation as the voluntary and intellectual in man-the internal corresponding to the voluntary, and the external to the intellectual.  Everything voluntary has its intellectual; one cannot exist without the other.  The voluntary may be compared to a flame and the intellectual to the light therefrom.

33.  Let it be clearly understood that with the angels it is the interiors that cause them to be in one heaven or another; for as their interiors are more open to the Lord they are in a more interior heaven.  There are three degrees of interiors in each angel and spirit, and also in man.  Those in whom the third degree is opened are in the inmost heaven.  Those in whom the second degree is opened, or only the first, are in the middle or in the outmost heaven.  The interiors are opened by reception of Divine good and Divine truth.  Those who are affected by Divine truths and admit them at once into the life, thus into the will and into action therefrom, are in the inmost or third heaven, and have their place there in accordance with their reception of good from affection for truth.  Those who do not admit truths at once into the will but into the memory, and thence into the understanding, and from the understanding will and do them, are in the middle or second heaven.  But those who live morally and who believe in a Divine, and who care very little about being taught, are in the outmost or first heaven.{1} From this it is clear that the states of the interiors are what make heaven, and that heaven is within everyone, and not outside of him; as the Lord teaches when He says: 

     The kingdom of God cometh not with observation, neither
     shall they say, Lo here, or Lo there; for behold the
     kingdom of God ye have within you (Luke 17:20, 21).