In the Inner Canon of Yellow Emperor (黄帝内经), human development is classified into 4 stages: Wise Person (贤人), Saintly Person(圣人), Outmost Person(至人), and Real Person(真人).
A wise person follows the laws of sky, earth, sun, moon, star, follows the law of yin-yang four seasons, lives in accordance with the methods and ways prescribed in the ancient period. Their age extended, but still limited. Typical spiritual practitioners falls into this category.
A saintly person positions himself in harmony with sky and earth and their laws, allows appropriate desire within the secular world, has no anger, does not depart form the world, but does not follow it blindly either, externally does not fatigue his form, internally does not have mind problem, strives at simple happiness, of self sufficiency, body stays health, spirit stays condensed, age reaches one hundred. Confucius (孔子) is an example of this type of person.
An outmost person aligns with Dao with pure virtue, harmonizes with Yin-yang, regulates with four seasons, departs from the world and the secular, accumulates essence to full the spirit, travels between sky and earth, sees and hears from afar. Life strengthened and extended. Chuangzi (庄子) is an example of this type of person.
A real person supports sky and earth, masters yin-yang, breathes essence and chi, abides one spirit independently, integrates body as one, lives long like sky and earth, without end, as the Dao. Laozi (老子) is an example of this type of person.
黄帝内经内，人类的发展分为四个阶段：贤人，圣人，至人，和真人。
贤人的法的天地日月，阴阳四季的生活规律，按照远古时期传下来的方法和途径去生活。他们的年龄延长，但仍然有限。一般修行的人就属于这一类。
圣人能与天地和谐的共存。他们在世俗的世界中有适当的欲望，没有愤怒，没有离开世间，但不盲目地跟着它。 外部不会疲劳其身体，内部没有精神的问题。 他们争取简单幸福的生活，自给自足，身体保持健康，精神保持简明，年龄能达到一百。孔子就属于这种类型的人。
至人与道唯一，能协调阴阳，调节四季，出离世间，积累到充满的精神，畅游天地之间，有超凡的视觉和听觉。生命能强化和延长。庄子就属于这种类型的人。
真人支持天地，支配阴阳，呼吸精气，抱神守一，生命跟天地，道一样，没有界限。老子就属于这种类型的人。