The philosophy of Yoga was expounded long ago on the Indian Sub-Continent of Asia, although the true origins are not so clear.
Yoga is perceived as many things, most of them quite accurate in some ways, and yet few of these perceptions are complete. Stretching, breathing, and meditating are all part of a typical yogi’s Practice.
Yoga-proper, however, is the yoking of Reality into a Whole. The notion of joining, of uniting or merging, is the meaning of Yoga. Purusha and Prakrti (as described in Samkhya philosophy). Consciousness and Matter.
In Practice, it might be pursued as a harmonizing of the Mind and the Body. It might be a matter of making connection between Individual and Collective energies. It might be a spiritual endeavor, seeking to merge with the Divine.
There are many Paths of Yoga.
The Yoga that is so popular today is generally traceable to Patanjali’s Yoga Sutras. This text sets out the Eight-Limbed (Ashtanga) Path of Yoga, or Raja Yoga.
Raja Yoga encourages attending to the Body, the Breath, and the Mind but there are recommendations regarding Behavior and Attitude as well.
These recommendations are referred to as Yamas and Niyamas.
The most popular aspect of Raja Yoga is Asana, the command and care of the physical body. Asana promotes strength, flexibility, and longevity. It has gained a strong foothold, along with Pranayama (breath-work) in the mainstream fitness culture.
The surging interest in Meditation makes several other aspects of Ashtanga Yoga popular. The meditative elements of Yoga are Pratyahara, Dharana and Dhyana.
The eighth aspect of Ashtanga Yoga is Samadhi, liberation into Ultimate Reality.
Not every person in a Yoga class is likely to be able to claim that they are on a quest for Samadhi, but Asana, Pranayama, and meditation are helpful tools for anyone living with Mind and Body.
Raja Yoga, as well as Jnana Yoga, Karma Yoga, and Bhakti Yoga, are all useful methods for this Human Experience.
Of course, understandings and interpretations of Yoga and related subjects are vast and diverse. Investigate your questions, and investigate the answers you find too!