I believe in both magic and sorcery. Witches heal or damage people using spells that they find in the "Book of Shadows". They can buy it, but real witches have one made by themselves or by their ancestors. In those spells witches invoke energy (spirits) to make what they want.
Magic is for magicians (not witchy business) and the difference between it and the sorcery is that the first one doesn't need goods to work, but just energy and mind. In my opinion witchcraft (sorcery) is material, magic is spiritual.