The essential function of human intelligence is discernment between the Real and the illusory or between the Permanent and the impermanent, and the essential function of the will is attachment to the Permanent or the Real. This discernment and this attachment are the quintessence of all spirituality; carried to their highest level or reduced to their purest substance, they constitute the underlying universality in every great spiritual patrimony of humanity, or what may be called the religio perennis; this is the religion to which the sages adhere, one which is always and necessarily founded upon formal elements of divine institution.