Engineers, software developers, hardware developers, technicians, and trades people have literally assembled this world (the built environs) from dust (raw materials in general).
Try googling for "the wizard book." See first result.
Marvel at the book's cover, http://mitpress.mit.edu/sicp/full-text/book/book.html
P.S. for a kinda-scientific treatment of "what if magic was real [and obeyed internally consistent laws]?", see ongoing scifi story http://qntm.org/ra
http://tvtropes.org/pmwiki/pmwiki.php/Main/MagicAIsMagicA
The description of Magic Engineering in Ra is worked out pretty entertainingly, with people setting up university departments, research programs, companies, etc., to apply magic to things like manufacturing and transportation.
Spoiler alert for Ra (no really, go read the story instead of this spoiler):
Va gur yngre puncgref vg'f funcvat hc gb ybbx yvxr gur ernfba gung "zntvp vf erny" vf abg gung vg'f n shaqnzragny cneg bs gur angher bs gur havirefr, ohg gung vg jnf vzcyrzragrq va gur cnfg ol uhzna orvatf sbyybjvat n grpuabybtvpny fvathynevgl, lrg gung gur crbcyr fghqlvat vg naq cenpgvpvat vg gbqnl qba'g xabj gung gung fvathynevgl unf unccrarq. (Gur choyvp jebatyl oryvrirf gung zntvp jnf nyjnlf n cneg bs angher.)
Gur rknpg ernfba gung gur trareny choyvp vf pbzcyrgryl hanjner gung gur fvathynevgl vf nyernql va gurve cnfg (be gung zntvp vf n uhzna perngvba!) vf fgvyy na rkpvgvat cbvag bs batbvat qvfchgr va gur fgbel, naq V'z dhvgr rkpvgrq gb svaq bhg gur nafjre.
(Thanks for the tvtropes article; it links to another one (http://tvtropes.org/pmwiki/pmwiki.php/Main/MinovskyPhysics) which mentions "Schild's ladder"; which makes their arguments ex vi termini pretty great!)