Individualistic Idealism, also known as Subjective Idealism, is primarily associated with George Berkeley.
Its central feature is the principle ``Esse est percipi'', meaning ``to be is to be perceived''.
It asserts that material objects do not exist independently of the mind that perceives them.
Physical objects are merely collections of ideas or sensations within the mind.
It denies the existence of inert matter, arguing that only minds (spirits) and their ideas are real.