Here are some thoughts on the Buddhist view of mind . . . The Buddhist school particularly associated with the statement “It’s all mind” is the Chittamatra, meaning ‘Mind-Only’ in Sanskrit. It is also known as Yogācāra because of its emphasis on meditative (yogic) practices of concentration. The most famous exponent of this school was Arya Asaṅga (c. 300-370 CE).
One feature of Chittamatra is the idea of multiple levels of mind. The deepest or most subtle level of mind (known as the root mind, or ‘consciousness-basis-of-all’) resides in the heart chakra. The heart chakra is not the same as the physical heart organ. It is at the level of the physical heart, but directly in front of the spine (by about two finger-widths). The heart chakra is part of the network of inner channels or meridians through which subtle energy winds (prana) flow. Mind rides these winds like a rider on a horse. The gross levels of mind are associated with the gross winds flowing through the 72,000 outer channels, but root mind is associated with the very subtle wind residing in the heart chakra.
According to Chittamatra, it’s root mind which transmigrates from life to life, carrying with it the accumulated karmic seeds. These seeds ripen as worlds, environments, bodies, minds, experiences etc, which is where the claim that “it’s all mind” comes from. While we continue to accumulate karma contaminated by ignorance, we remain trapped in the cycle of contaminated rebirth (samsara), and the worlds, bodies, minds etc which we experience are contaminated. Arya Asanga’s teacher Maitreya said that when our mind is pure our world will be pure.