WHY/WHAT IS YOGA
Today, "yoga" often stands for physical, postural exercises of the sort that one does for a finite duration.
In the South Asian tradition, "yoga" was the generic term for meditation and discipline. In this broad sense, "yoga" was not a term for a specific practice that one undertakes occasionally, but for a disciplined approach to living.
In sharp to the Western tradition, were reason was often presented as a concern or search for the truth (an idea we see beginning with Plato), ancient philosophers of yoga from South Asia adopted a critical attitude to the truth and the facts: many truths about our world are not reasonable but a result of pathological responses to trauma and events.
Moreover, as one learns in basic introductions to critical thinking and logic classes, truth is neither necessary nor sufficient for reason. Learning to be reasonable is about drawing a distinction between reason and the truth and the facts.
Yogas are developed practices of reasonable living in light of stupid facts, constructed out of pathological habits. The point of reasonable living is not to reify the pathological patterns of the past, but to transform ourselves and the public world, so that we (all can) live in accordance with our interests as individuals.
Yoga Philosophy is a contemporary revival this ancient, rational, transformative approach to living: push against restrictions, determine one's own ideals, move from old habits to a freer future: tapaḥ svādhyāyeśvara-praṇidhānāni kriyā-yogaḥ (Yoga Sūtra II.1)