The pinnacle of yoga is the absorption of the mind in the object of its concentration. The whole technique borders upon an attunement of the subjective consciousness, in its wholeness, to the structure of the object of concentration. Normally, the object is severed from consciousness so that it exists as an independent, material something, totally incapable of reconciliation with the nature of consciousness. However, under the scheme of the Samkhya, it does not appear that in the perception of an object the consciousness stands entirely independent of the influence exerted by the object upon itself or, on the other hand, the attachment and the relationship which it wishes to project, for some extraneous reason, in regard to the object itself. According to the Samkhya system, the object is totally independent of the subject which is consciousness, the object being a mode of prakriti and the consciousness being the Purusha manifest through an individuality when it is engaged in an act of cognition or perception. However, the Purusha, according to the Samkhya, is infinite in its nature and hence its assumption of the role of a percipient locally placed as a finite entity in respect of the object of its knowledge is unimaginable. This involvement of the infinite Purusha in an association with finitude consequent upon its relationship to prakriti's modes is its bondage. The freedom of the Purusha is its return to its original status of infinitude by way of abstraction of its relations with every form of objectivity, which is prakriti in some degree of its manifestation. The yoga system of Patanjali is, in the end, a gospel on the necessity of severing all relationships on the part of consciousness in respect of every type of involvement in externality or objectivity, beginning with social relationships, involvement in the physiological organism of the body, the psychic structure of the antahkarana, or the internal organ, the causal body of ignorance, and ending in the very impulsion to enter into any mode of finitude, whatsoever. Yama, niyama, asana, pranayama, pratyahara, dharana, dhyana and samadhi are these stages of the gradual withdrawal of consciousness from outward contact and a simultaneous rising into wider and wider dimensions of itself, culminating in infinitude which is its quintessential essence. While the dissociation of consciousness from relations with society, body, mind and intellect, etc. is achieved through the practice of yama, niyama, asana, pranayama, pratyahara, dharana and dhyana, which are intelligible to the seeker of yoga to some extent, the higher attunement known as samadhi at which we have only meagre hints in the Sutras of Patanjali, is more difficult of comprehension and may appear humanly impossible for minds which are socially involved and sunk deep in body-consciousness to the exclusion of the awareness of any other value. 

While concentration is defined as the tethering of the mind to a point of attention, whether external, internal or universal, meditation is described as a flow which is continuous, as a movement from the meditating subject to the object of meditation. There are four factors involved in dharana, or concentration, namely, the exclusion of extraneous thoughts which are irreconcilable with the thoughts of the object of concentration, the thought of one's own subjectivity as a concentrating principle, the process of concentration, and the object on which the concentration is practiced. But in dhyana, or meditation, there are only three processes and the question of excluding extraneous thoughts does not arise here, since the thought in meditation has deepened itself to such an extent that it can have no awareness of anything outside the purview of the object of meditation.