Related articles: Of Magic and Machine
Magic — to which altered states of consciousness are the key  — has real effects because reality is not separate from consciousness, nature is not separate from mind . Which leads me to two assumptions.
1. The degree to which we can satisfactorily describe a system as separated from an observer  corresponds precisely to the degree to which magic cannot influence reality. This gives rise to such notions as magic cannot violate the laws of physics.
2. The corollary that the more an observer is required to satisfactorily describe a system, the more amenable is that system to magical influence. This gives rise to such notions as magic has something to do with quantum mechanics.
This is the basis of my synthesis of magic and cybernetics: that magic describes the (means to) altered states of consciousness required for desired effects, and cybernetics describes the non-trivial relationship between the observer and the observed whereby altering my state of consciousness alters the world I am conscious of.
Related: The difficulty with proving magical efficacy is that magic is necessarily a non-trivial phenomenon, while scientific experimentation necessarily trivializes it.
Notes & References
- Peter J. Carroll, Liber Null and Psychonaut.
- Cf. Gregory Bateson, Mind and Nature: A Necessary Unity.
- Urban Kordeš, “Participatory Position.” Cf. Heinz von Foerster’s notion of trivialization (“Perception of the Future and the Future of Perception,” also Understanding Systems: Conversations on Epistemology and Ethics).