The trait I have in mind is the following. Most techniques labelling themselves yoga have the effect of generating Altered States of Consciousness (ASC) (Wikipedia link). By that I mean specific observable mind-states, which are dissimilar to our daily normal states of mind. For short we could call ASC trance. Within psychology and medicine ASC are observable and measurable physio-psychological states. They are – because they are tangible facts – the chosen foundation for our further discussion. ASC does clearly not define yoga, because many other techniques and substances can also generate ASC. Yoga just represents a general group of ASC generating techniquesâ, which conventionally has been labelled yoga. Yogic generated ASC can be the direct goal of practice or it can be a side effect – this is not crucial. Most self proclaimed yoga practitioners through history would agree on this abstract level that their yoga practice is leading to a state of mind different to their normal state of mind. (At the end of Appendix 1 there is a detailed discussion of ASC.)
It may be asked: How is this possible? The Yoga Easy Pose reply given by the author is that the spiritual adept remains still, unruffled, above the feelings of pleasure and pain. He lives anywhere. The expression anywhere in the above verse means Yoga Easy Pose whichever place appears to him suitable for shelter because of its purity or otherwise. He shuns unholy places like cremation grounds or animal houses as these are not congenial to his manner of living. He lives at the place which automatically appears before him without having to search for it.