Georg Hegel, German idealism.

A philosophy that matter is an illusion and that the only reality is that which exists mentally. Some of the proponents were the German philosopher Georg Hegel and the Irish philosopher Bishop George Berkeley.

Idealism is the family of views which assert that reality, or reality as we can know it, is fundamentally mental, mentally constructed, or otherwise immaterial.

Religious and philosophical thought privileging the immaterial or supernatural over the material and natural is ubiquitous and ancient. However, the earliest extant arguments that the world of experience is grounded in the mental derive from India and Greece.

The Hindu idealists in India and the Greek Neoplatonists gave arguments for an all-pervading consciousness as the ground or true nature of reality.

The 20th century British scientist Sir James Jeans wrote that “the Universe begins to look more like a great thought than like a great machine”