The conception of avidyā or nescience is here not negative but has a definite positive aspect. It means that kind of knowledge which is opposed to true knowledge (_vidyāviparītaṃ jñānāntaramavidyā_). This is of four kinds: (1) The thinking of the non-eternal world, which is merely an effect, as eternal. (2) The thinking of the impure as the pure, as for example the attraction that a woman’s body may have for a man leading him to think the impure body pure. (3) The thinking of vice as virtue, of the undesirable as the desirable, of pain as pleasure. We know that for a Yogin every phenomenal state of existence is painful (II. 15). A Yogin knows that attachment (_rāga_) to sensual and other objects can only give temporary pleasure, for it is sure to be soon turned into pain. Enjoyment can never bring satisfaction, but only involves a man further and further in sorrows. (4) Considering the non-self, e.g. the body as the self. This causes a feeling of being injured on the injury of the body. At the moment of enjoyment there is always present suffering from pain in the form of aversion to pain; for the tendency to aversion from pain can only result from the incipient memory of previous sufferings. Of course this is also a case of pleasure turned into pain (_pariṇāmaduḥkhatā_), but it differs from it in this that in the case of pariṇāmaduḥkha pleasure is turned into pain as a result of change or pariṇāma in the future, whereas in this case the anxiety as to pain is a thing of the present, happening at one and the same time that a man is enjoying pleasure. Enjoyment of pleasure or suffering from pain causes those impressions called saṃskāra or potencies, and these again when aided by association naturally create their memory and thence comes attachment or aversion, then again action, and again pleasure and pain and hence impressions, memory, attachment or aversion, and again action and so forth.