For something to be cast down or cast out generally refers to a rather dramatic move from a higher spiritual state to a lower one. In most cases it's used in reference to evil desires or false thinking – or people spreading desires and false thinking – being removed and banished, even condemned to hell. Some uses are more moderate, though, and sometimes – when Moses casts down his rod in performing a miracle, for example – it signifies the sudden inflowing of the divine into the natural world.

(Referenser: Apocalypse Explained 497, 1175; Apocalypse Revealed 252, 552, 835, 872; Arcana Coelestia 2657, 6693, 6948; The Apocalypse Explained 1181)

552. It was cast to the earth, and its angels were cast out with it. This symbolically means that they were cast into the world of spirits, which is midway between heaven and hell, from which a direct conjunction is formed with people on earth.

The earth to which the dragon is said to have been cast means the world of spirits, because this world lies directly under the heavens, and when anyone is cast out of heaven, he does not sink immediately into hell, but onto the land in this world that is the nearest one beneath. For this world is midway between heaven and hell, being situated below the heavens and above the hells. More on this world may be seen in the book Heaven and Hell (London, 1758), nos. 421-535.

The people in this world all communicate directly with people on earth. The dragon and its angels consequently communicate with people caught up in falsities and their accompanying evils, owing to the heresy they have accepted regarding faith alone. The text accordingly says later in verse 12 of this chapter,

Therefore rejoice, O heavens...! Woe to the inhabitants of the earth and the sea! For the devil has come down to you, having great wrath, knowing that he has a short time." (Revelation 12:12)

We are also told in verses 13-17 that the dragon pursued the woman into the wilderness, and went off to make war with the rest of her offspring.

It should be known that in respect to his affections and consequent thoughts, everyone is present in a society with people in the world of spirits, and indirectly through them with people either in heaven or in hell. Everyone's life depends on that conjunction.