The combination of eyes, ears, nose, tongue, body and mind is called six, that is, physiological nerve function, in terms of psychological and physiological media function. There are optic nerves in the eyes, auditory nerves in the ears, olfactory nerves in the nose, olfactory nerves in the tongue, sensory nerves in the body and cranial nerves in the brain, which are the basis of the medium between the mind and things, so it is called six.
Fourth, it refers to four material factors: soil, water, fire and wind.
"Four Spaces" refers to the air, sky, ground and air, and human space.
What are the four empty ones? In fact, the standard answer is given in Tao Te Ching. "The old road is big, big, big, and the National People's Congress. There are four in the domain, and people live in one. "
Extended data
"Everything is empty" means that everything in the world, whether sentient or senseless, animals or plants, as big as cosmic life, as small as a flower and a grass, is composed of four elements: earth, water, fire and wind.
The "earth" is big and hard, and can support everything, such as human hair, teeth, claws, skin, bones, muscles and brain. "Water" is big and wet, and it can absorb everything, such as human saliva, purulent blood, saliva and foam in body fluid, phlegm and tears, urine and so on.
"Fire" is big and warm, and it can mature everything, such as human body temperature and heating. "Wind" is powerful, it is flowing and can grow everything. For example, a person's breath belongs to the wind.
For example, if a flower wants to bloom, it must have fertile soil, suitable water, warm sunshine and flowing breeze. Without a big one, it can't blossom and bear fruit. People can survive because of the combination of four evils. If the four evils are not coordinated, they will surely get sick. Even if the four evils are dispersed, they will not be far from death. The so-called edge together, while scattered into, this is the truth.
The so-called "nothing" means that everything is born because of many things. If there is no cause and effect, nothing will be born. Everything is empty, not only when people are scattered, but also when people are healthy and blooming, the height of the body is not timely, that is, everything in the universe has no substance. To say "yes" is to say "empty" truthfully.
References:
Baidu Encyclopedia-all four are empty
References:
Baidu encyclopedia-six clean roots