Yoga takes one only as far as kaivalya , which is the perfection of the singular, going "solo." All other yoga systems, including bhakti , also pass through kaivalya , in the sense that they are the establishment, as far as is possible, of the self in the self, without which relationship is meaningless. But in the relishing of bhakti-rasa , it is indeed only a stage: both the work of vidhi-bhakti and yoga are elements of the pravartaka stage or preliminary stage of practice in rasika-bhakti . This is because in yoga, the culture of love is restricted to the yamas and niyamas and some other general internalizing processes, whereas in bhakti, love is the culmination, both the means and the end. In other words, in yoga, love is one of the means, and a subordinate one at that, but in bhakti, love is the one and only all consuming goal. Nevertheless, the gains of yoga, both as a psychological force (as expounded on in the Yoga-sutra ) and as a psycho-physical force (fro...