The human mind is vastly complex, much beyond our current understanding. Because of this, there is no way to be completely sure of it's limits, but as far as I know, the "limits" of magick are simply as far as you place limits on yourself. Subconsciously all of us set our own set of rules usually influenced by the environment that develops our social psyche, and this set of rules can limit you in what you do. Sometimes it comes down to working past the social norms programmed into your mind.
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