They have no purpose of their own to serve, but they all are always evolving, as Dr. Seal says, “ever from a relatively less differentiated, less determinate, less coherent whole, to a relatively more differentiated, more determinate, more coherent whole”[7] for the experiences and liberation of purusha, or spirit. When in a state of equilibrium they cannot serve the purpose of the purusha, so that state of the guṇas is not for the sake of the purusha; it is its own independent eternal state. All the other three stages of evolution, viz. the liṅga (sign), aviśesha (unspecialised) and viśesha (specialised) have been caused for the sake of the purusha.[8] Thus Vyāsa writes:—[9] “The objects of the purusha are no cause of the original state (_aliṅga_). That is to say, the fulfilment of the objects of the purusha is not the cause which brings about the manifestation of the original state of prakṛti in the beginning. The fulfilment of the objects of the purusha is not therefore the reason of the existence of that ultimate state. Since it is not brought into existence by the need of the fulfilment of the purusha’s objects it is said to be eternal. As to the three specialised states, the fulfilment of the objects of the purusha becomes the cause of their manifestation in the beginning. The fulfilment of the objects of the purusha is not therefore the reason for the existence of the cause. Since it is not brought into existence by the purusha’s objects it is said to be eternal. As to the three specialised states, the fulfilment of the objects of the purusha being the cause of their manifestation in the beginning, they are said to be non-eternal.”