In response to a reply in Why Jewish Yoga. Rabbi Meir Goldstein brought two questions to mind that I wanted to address in length.
Rabbi Meir had asked – Is there a way to authentically meld the two different traditions? Is it better to maintain the integrity of each as a stand alone practices that each speak to my neshama? Is there value added to synthesis?
Here I see two questions that are related :
1. Can the different traditions be melded and maintain authenticity (I am presuming in both)?
2. Is there any benefit to melding the traditions?
To answer the first simply, my opinion is (obviously); Yes.
If I had to sum up Yoga in one sentence – it is:
The spiritual union of the individual with the Ultimate; Ineffable, Divine; Singular Being through the practice of ethics, examined living, physical ritual, and meditative practice.
The Asanas – or physical part that take place in yoga class are a part of the whole. A moving meditation.
Yoga, as a spiritual tradition, has a nuanced and complex oral/mythical history and a history based on body of evidence – and I want to be careful to respect both.
Approximately 3000-5000 years ago – we have the Vedic period. The earliest Vedic texts and carvings show a history that begins with the Brahmanistic  concept of a singular ineffable deity as creator. This, as noted by many historians, was the predecessor to the Hindu religion.
Roughly speaking the next period of of Yogic philosophy comes around 6th century BCE and is infused in the Hindu tradition with the Bhagavad Gita text and the entity Krsna, as a corporeal manifestation of the God-head speaks of Yoga and Yoga moves from a Shamanistic and/or Ritualistic part of Brahmanism to a definite Hindu linage. ( notes: Brahman is the Hindu religion is still recognized as the supreme singular universal spirit and there are still pure Brahmanisms that practice today – but it is far more rare .)
Fast forward to a more modern period and we see that the Hindu practice has grown and developed over time and in actuality has been a combination of teachings form the Yoga Sutras of Ptanjali ( there is a debate whether these were written 3000 BCE or 200 CE or somewhere in between – quite the spread), Hindu philosophy, individual Guru’s teachings and – wait for it – English gymnastics and exercise disciplines of the YMCA.
As with any long standing traditions, there is an evolution in its development, and one has to ask; what is authentic Yoga. The answers are as numerous as there are teachers.
In the modern period there are two main thrusts I wish to focus on in this response. One is the idea that Yoga is purely a Hindu system and must be taken back and maintained as a Hindu system as purposed by fundamentalists such as the HAF – and another, of which I am in favor of, in which Yoga has no religious affiliation and is a spiritual, ethical and physical science open to all.
To quote Swami Vishnu Devananda – “anyone can practice Yoga, not matter what their age, condition, or religion…You can meditate on a flower, the Star of David, or the Cross, just as well as on Krishna or Rama.”
Then what about authentic Judaism?
Physical postures combined with meditation and an ethical and spiritual practice of cleaving to the divine are not foreign concepts to all of Judaism.
We have within our tradition, evidence to support the concept of the early Jewish mystics chanting mantra like Hebrew phrases in particular physical postures to attain enlightenment – these Merkava mystics are the proto-Kaballists and the root of the limbs that have grown in to what is our modern Kaballistic texts. Even today there are modern mystics such as Ophanim Meditation that claim lineage or rejuvenations to these systems.
Sadly as noted by Aryeh Kaplan in his books, such as Jewish Meditation – much of this mystical heritage has been lost, and this is devastating to Judaism as a whole.
Which bring me to my wrap up and the answer to the second question : is there any benefit.
With the loss of much of our meditative and engaged practice – we have gates that are closed to us that beg to be opened, mindfully and with wisdom.
Carefully combining the authentic Jewish mystical meditative traditions of the BeSHT, the Merkavah Mystics, Kaplan and others, with the deeply meditative practice of Yoga can be both authentically Jewish, Authentically Yogic, and beneficial to those that practice either or both.
Further suggested bite-sized readings on this:
 “Brahman is the one supreme, universal Spirit that is the origin and support of the phenomenal universe.” The Oxford Dictionary of World Religions, ed. John Bowker, OUP, 1997
 The Sivananda Companion to Yoga, Fireside Books, 1983, 2000