Vajrayana and Yogacara

Yogācāra thought seems to provide a natural philosophical background for tantric rituals. If we want to explain why practices like the visualization of maṇḍalas, offerings, the mental transformation of one’s environment into the pure abode of the deity, and even the visualization of oneself as the central deity in the maṇḍala are supposed to lead to progress on the path to enlightenment, rather than constituting a particularly ritualized form of daydreaming, we need to presuppose that the world we ordinarily inhabit, the world of atoms, tables, chairs, and galaxies, is of the very same nature as the constituents of tantric practice. If the entire world is fundamentally mental in nature it is easier to understand how it may be possible to transform it into a different world by purely mental techniques. If, as the Yogācāra believes, how we perceive the world is crucially influenced by karmic imprints in our mind (that is, by purely mental phenomena), we can understand how one might attempt to transform the world of saṃsāra into the nirvāṇic world of a pure realm by trying to affect these imprints, and to replace them by others so that the world then naturally appears to us like a pure realm.

(From Jan Westerhoff's The Golden Age of Indian Buddhist Philosophy, p. 199)