Ah. At that point Mal had finished quoting the article and moved into its own comments ...
How about we just rephrase that as "spirit entities" -- beings with their own intelligence, personality, aims, goals, agendas, feelings, thoughts, views, etc. that exist on another level or in another realm, one that intersects with the physical realm but would not be bound by its constraints.

Better?

If you had geometry in school you might remember mapping points on a 3-d grid, with X, Y, and Z axis. Well, add time to that grid -- add one more axis, we can call it "T" -- to make it four-dimensional rather than three, and you have a different type of "space" altogether from what 3-d creatures like humans would be accustomed to moving through without constraint. These entities come from that region or something higher, hence Their ability to intersect what humans experience as reality in a number of creative ways, appearing to move both forward and backward in time, and to co-locate in different places at the same "time moment" to the human perception.

Sorry, probably making this more complicated rather than easier.

Ever read the book Flatland? Do so sometime, then just move everything in the story "up" one dimension (from 3-d interacting with 2-d up to 4-d interacting with 3-d) and you'll "get it".