Kirtan is an ecstasy-inducing, call-and-response form of mantra chanting that is currently undergoing a worldwide renaissance. The primary musical feature of kirtan is the use of call and response, a figure that also deeply informs Western bluegrass, gospel music and jazz. The form is simple: a lead group calls out the melodies and the mantras. The crowd responds, clapping and dancing as the rhythms build and accelerate.
The intention of Kirtan is consciousness-transformative, directing the singers to vanish into the song as drops merge into the ocean. Sanskrit is the mother tongue of many modern languages, and a kind of periodic table of elemental sound meaning. The mantras are primarily recitations of names given to the divine. But perhaps the true understanding of the mantras can be found in the sense of unity, well-being and timelessness that they elicit. The mantras quiet the mind, and the music frees the heart. Ecstasy is both the process and the product.
The Bhaktis wrote ecstatic love poems, and went around singing all the time. Their message was simple: Cultivate joy. See the divine in one another. They taught Sanskrit mantras to common people using simple melodies, accompanied by handclaps and finger cymbals and drums. The Bhaktis had no use for orthodoxy. They saw the expression and form of the divine in every direction they looked. From this perspective, even music that cannot be characterized as traditional can still be expressive of the Bhaktis' original intention.
Mantras are intended as a tool with which the spirit can release itself from the prison of attachments created in the mind. It's not unfair to say that the chanting of mantras is intended to be a completely mindless activity, since the intention of chanting is to create an ecstatic state of awareness that is beyond mind. Yoga doesn't ask us to believe, it asks us to practice, examining our experience until we can witness the truth in the book of our own heart. No one else can read it for us, or tell us what it means. Ultimately, whether mantras are ancient wisdom, complete nonsense or potent metaphor depends on the intention and experience of the one who sings them.