Is yoga secular or religious?
That's the conundrum at the heart of a new legal battle in Encinitas, Calif., over the teaching of yoga in public schools.
In a lawsuit filed last month, a couple with two children in the Encinitas schools charge that the district is unconstitutionally promoting religion by giving yoga classes twice a week to students during the school day.
School officials insist that the yoga classes are for physical fitness - and have nothing to do with religion or religious indoctrination.
The outcome of case could impact hundreds of other public schools nationwide that incorporate yoga postures and breathing exercises into their wellness and fitness programs.
Because "yoga" is used to describe a bewildering variety of classes and programs that dot the American landscape, from retreat centers and ashrams to shopping malls and gyms, it's easy to forget that yoga originated in ancient India as a school of Hindu philosophy.
Many yoga practitioners embrace the religious roots and spiritual meaning of yoga while many others view yoga largely as a healthy exercise and stress reduction regimen.
Public schools, of course, adopt the "healthy exercise" definition in order to comply with the First Amendment's prohibition of school promotion or endorsement of religion.
That's why yoga programs adopted by schools all claim to be secular, although they negotiate the traditional religious framework in a variety of ways.
On one end of the spectrum, a program offered to schools called "Grounded" retains Sanskrit terms such as asanas (poses) and doesn't shy away from referencing the Chakra System, the "seven major energy centers in the body" as understood in many Eastern religious traditions.
On the other end, Yoga Ed - which claims to be in 150 schools in 27 states - eschews Sanskrit terms and avoids anything that could be construed as religious teaching (meditation, for example, is "time in"). According to Yoga Ed, yoga is science, not religion.
Not surprisingly, attempts to completely secularize yoga have met with resistance - and not just from Christian parents like those in Encinitas.
Many Hindus argue that authentic yoga is inseparable from its philosophical roots in Hinduism. To underscore this point, the Hindu American Foundation launched a "take back yoga" campaign in 2010 to remind people of yoga's Hindu origins.
Moreover, many yoga practitioners view yoga postures and breathing exercises as inherently spiritual, giving spiritual benefits even to those who practice yoga solely for health reasons without any interest in the religious meaning of their practice.
To what extent, if any, yoga practices can be fully divorced from religious roots or spiritual efficacy is a metaphysical and theological debate that can't be resolved in a court of law.
What courts can and must do, however, is determine if a school's yoga program explicitly conveys religious teachings or messages. This means that the more a yoga program avoids religious language and metaphysical explanations, the more likely it is to be upheld as constitutional.
If the court does uphold yoga classes in Encinitas (as is likely), schools elsewhere will get the message that yoga can be sufficiently secularized to pass constitutional muster. Parents who object will have no recourse but to opt their children out (an option Encinitas currently offers).
The larger question of whether yoga practices are inherently spiritual will remain unanswered - and hotly debated.
Is yoga still yoga when stripped of all religious trappings? That's a religious issue the First Amendment can't resolve.