So, how do people interpret 'natural' movement in regards to the rego guidelines?
I mean, it seems to me no movement for dirt or rocks is natural. And things like falling rocks tend not to need magical assistance.
Making a hole by having dirt move out of it is normal..ie you can do that with a shovel.
Making dirt spin around in the air or assume the shape of a person (and move) is not normal.
Think about it this way:
You are a peasantt, digging a hole in your masters field. Along comes a Magus...the Magus agrees to help out for some directions.
Now the Magus moves this dirt out of the hole into a large pile. If the dirt just flew out into that pile, it might be a little strange, but its a welcome sight. Now if you had the dirt in question form into little soldiers and walk out, that might scare the life out of a simple fella like you. (Spirits and demons!)
My $.02
A downward movement is natural, but might be impeded by, say, architecture. It's natural for the ceiling to fall downward, unnatural that it hangs out up there all the time.
Okay, but then when would you ever use a spell for 'natural' movement?
(This is mostly me playing devil's advocate, by the way.)
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There's plenty of rocks hanging out in unnaturally high positions. A cliff, for instance, is unnatural, because all of that rock ought to flatten out in an effort to reach its natural place, the center of the universe. Caves and buildings are unnatural, because there's rock, which is naturally lower than water or air, above water or air. If someone has tossed a big rock over the city walls, it's only sort of natural that it stays up there en route; the air that it pushes out of its way whirls around behind it (I think that this was called "whirling winds," and you have to have it in your belief system if you don't have inertia) and pushes the rock along. But it would be natural for the rock to just fall straight down at any time. Plenty of applications.