Prakṛti, though a substantive entity is yet a potential power, being actualised as its various modifications, the aviśeshas and the viśeshas. Being of the nature of power, the movement by which it actualises itself is immanent within itself and not caused from without. The operation of the concomitant conditions is only manifested in the removal of the negative barriers by which the power was stopped or prevented from actualising itself. Being of the nature of power, its potentiality means that it is kept in equilibrium by virtue of the opposing tendencies inherent within it, which serve to obstruct one another and are therefore called the āvaraṇa śakti. Of course it is evident that there is no real or absolute distinction between the opposing force (_āvaraṇa śakti_) and the energising force (_kāryyakarī śakti_); they may be called so only relatively, for the same tendency which may appear as the _āvaraṇa śakti_ of some tendencies may appear as the _kāryyakarī śakti_ elsewhere. The example chosen to explain the nature of prakṛti and its modifications conceived as power tending towards actuality from potentiality in the _Vyāsa-bhāshya_ is that of a sheet of water enclosed by temporary walls within a field, but always tending to run out of it. As soon as the temporary wall is broken in some direction, the water rushes out of itself, and what one has to do is to break the wall at a particular place. Prakṛti is also the potential for all the infinite diversity of things in the phenomenal world, but the potential tendency of all these mutually opposed and diverse things cannot be actualised together. Owing to the concomitant conditions when the barrier of a certain tendency is removed, it at once actualises itself in its effect and so on. We can only expect to get any effect from any cause if the necessary barriers can be removed, for everything is everything potentially and it is only necessary to remove the particular barrier which is obstructing the power from actualising itself in that particular effect towards which it is always potentially tending. Thus Nandī who was a man is at once turned into a god for his particular merit, which served to break all the barriers of the potential tendency of his body towards becoming divine, so that the barriers being removed the potential power of the prakṛti of his body at once actualises itself in the divine body.