What is metaphysics? What are the characteristics of metaphysics? What factions can be divided into internally?

Metaphysics and obvious learning are two kinds of ancient knowledge. Its specific history can be searched by Baidu Encyclopedia, so I won't go into details.

Metaphysics can be roughly divided into five techniques: mountain, medicine, life, physiognomy and divination.

Mountain is practice. Medicine is medical skill, and the masterpiece is Huangdi Neijing. Life is numerology, four pillars and eight characters, purple bucket number. Face to face, hand in hand, feng shui. Divination is divination, including "adding and subtracting divination" and so on.