प्रकृतिं पुरुषं चैव विद्ध्यनादी उभावपि।
विकारांश्च गुणांश्चैव विद्धि प्रकृतिसम्भवान्।। १३.२० ।।
Summary Translation:
Material nature and the living entities should be understood to be beginningless. Their transformations and the modes of matter are products of material nature.
This verse provides the distribution of labor between the body and the soul. Krishna explains that Prakriti (nature) is the cause of Karya (the effect or the body), Karana (the instruments or senses), and Kartritve (the sense of doership in the material sense). This analysis focuses on the mechanics of action. Every physical movement, every sensory perception, and every physiological function is a product of material nature. When a hand moves, it is the result of biological and physical laws—nature acting upon nature. However, the second half of the shloka introduces a different dimension: Purushah sukha-duhkhanam bhoktritve hetur uchyate. The Purusha (soul) is the cause of the experience of happiness and distress. This religious interpretation is profound: while the body performs the work, the soul experiences the result. This creates a subject-object relationship that is essential to understand for spiritual progress. The problem for most people is that they confuse the two; they believe the soul is the doer of the physical act and that the body is the experiencer. Krishna corrects this by showing that the soul's role is that of a Bhokta (enjoyer or experiencer). The Hetu or cause for material activity is Prakriti because the soul, being spiritual, has no inherent desire to move matter. It is only when the soul identifies with the material body that the cycle of action and reaction begins. The detailed analysis of Karya-karana indicates that the entire machinery of the world is self-sustaining and mechanical. It is like a complex machine that is capable of running, but the machine itself cannot feel. It is only the conscious driver—the soul—who feels the joy of the ride or the pain of a crash. This shloka helps the devotee to realize that their true self is not the one sweating, laboring, or physically struggling. Those are functions of the material field. The true self is the silent witness who is currently experiencing these conditions. By isolating doership to Prakriti, Krishna removes the burden of false ego, allowing the devotee to perform their duties without being psychologically crushed by the physical toll of action.
The deep philosophical significance of Shloka 13.20 lies in the definition of Bhoktritvam (the capacity to experience). Matter is insentient (Jada). No matter how complex a physical system becomes, it cannot feel happiness or distress. Happiness and pain are attributes of consciousness. Thus, the Purusha is the necessary ingredient for any experience to occur. Philosophically, this verse explains the Why of our existence in the material world. We are here as Bhoktas, seeking enjoyment through the Karya and Karana provided by Prakriti. The tragedy, according to this analysis, is that the Purusha, which is capable of infinite spiritual bliss, chooses to experience the tiny, flickering Sukha and Duhkha of the material world. This shloka also addresses the concept of causality. Prakriti is the upadana-karana (material cause) of the body and senses. It provides the ingredients. But the presence of the Purusha is what makes the experience real for the individual. If there were no soul in the body, the body could still be moved by external forces, but there would be no one to say I am happy or I am sad. The religious significance of this is that it highlights our responsibility. While the body's movements are governed by nature, our experience is determined by our consciousness and its attachments. This leads to the realization that to change our life, we don't necessarily need to change the physical world (Prakriti), but we need to change the experiencer (Purusha's state of awareness). This verse provides a logical structure to the concept of detachment. If I am the experiencer but not the doer, I can learn to watch the body perform its duties like an actor on a stage. This philosophical distance is the key to equanimity. It allows the seeker to navigate the Sukha and Duhkha of life without being lost in them, recognizing that these feelings are just the reports coming from the field of Prakriti to the conscious soul. The conclusion here is the liberation from the Doer-Complex, which is the root cause of anxiety and karmic bondage.