Subjective idealism is one of the basic forms of idealism philosophy. Subjective idealism regards some ontological subjective spirits, such as feeling, experience, mind, consciousness, idea and will, as the source and foundation of the emergence and existence of everything in the conscious world, and everything in the conscious world is derived from these subjective spirits, which are all manifested.

China's theory of mind and nature in the Song and Ming Dynasties, such as "mind is reason", "my mind is the universe", "nothing outside the heart" and "unreasonable outside the heart", as well as Becker's thoughts of "being is perception" and "things are a collection of ideas", are all representative and typical subjective idealism.