Really, a jiva is neither the material nor the efficient cause of the material-karmas but only the agent of its own emotional states or bhavas. Therefore, it is only from the practical standpoint that the jivas are described as enjoying happiness and misery which are the fruits of material karma. In fact, the jiva is the possessor of consciousness only. Atman or jiva is the agent of its own bhavas, as it causes its own resultants. In an important sense, science of karma has been described as the science of spirituality.
Spirituality aims at unfolding the real nature of spirit or self.
But to know the self is also to know that it is different from the non-self, with which it is in beginningless conjunction. Karma is the material basis of bondage and nescience of the soul. This is determined by the nature, duration, intensity and quantity of karmas. It is therefore clear that the science of karma is a necessary part of the science of spirituality. Unless we have a thorough knowledge of the karmas, we cannot know about the true nature of spirit or self.