Based on Theravada Buddhism.
Earth, water, fire and wind are also called the four major elements. They are the ultimate color that makes up the world and are also called the true color. The four elements and the 24 colors created by the four elements form the smallest material unit in this world, called the rupa.
There are four reasons for the occurrence of these physical phenomena: karma, spirit, season and food
Karma-------brought by karma, like eyes; , ears, nose, tongue, body, sex, etc.
Born by the mind - the material produced by the heart For example, if we want to take something, the material produced by the heart will be passed on. by hand, directing the hand Go get something.
Seasonal birth – no features of life, such as stones and plants, etc. This is the rupa produced by the fire element. There are also seasonal forms ins the human body, such as the seasonal raw food element, the eight dharma kalapas.
Eating raw materials ----- the color kalapas produced by the food, such as the food produced by the man. digestion of the body and its spread throughout the body.
The specific theory of materiality is recorded in detail in the Theravada Abhidhamma, which can be personally verified through practice.
There is no need to believe in idealism and illusion, which cannot be verified. Pure metaphysical speculation has nothing to do with true Dharma.