All is mind, the Universe is Mental.

This principle embodies the truth that All is Mind. It explains that the All is the substantial reality underlying all the visible manifestations and appearances that we categorize as the material universe: matter, energy, and all that is apparent to our material senses. This entity, the all, is pure spirit, which is unknowable and undefinable, but is regarded in the most ancient traditions as a universal, infinite, living mind. Human beings, in futile attempts to describe the All, attribute to it characteristics that fall within the realm of what is comfortable and comprehensible. This is theology: the assigning of human qualities to the supreme in order to comprehend the incomprehensible. Thus, the all is always depicted as man and is actually given a personality. In reality this axiom explains that the universe is a mental creation of the All; that is to say, the All is everything and everything is the All. This principle also explains the true nature of energy, power, and matter, and how these are subordinate to the mastery of the mind.

References

Chandler, W. (1999). Ancient Future: The Teaching and Prophetic Wisdom of the Seven Hermetic Laws of Ancient Egypt. Atlanta, Georgia: Black Classic Press

Three Initiates. (1936). The Kybalion: The Hermetic Philosophy of Ancient Egypt and Greece. Chicago, Ill.: The Yogi Publication Society