Complex sentence: With this interest came a desire by medical professionals to learn acupuncture without the difficult theory, which includes Taoist cosmology and sometimes borders on shamanism and mysticism, all of which can be difficult for Westerners to understand.
Split into simpler sentences: With this interest came a desire by medical professionals to learn acupuncture without the difficult theory. Some traditional chinese medicine theories include reference to philosophies of Taoist cosmology and to some Westerners these philosophies border on shamanism and mysticism, all of which can be difficult for some Westerners to understand.