Arjuna opens Chapter 13 by asking for precise definitions of six fundamental philosophical terms. He addresses Krishna (keśava) and says: I deeply desire to know and understand (etad veditum icchāmi) the following subjects: material nature (prakṛtiṃ), the conscious enjoyer or soul (puruṣaṃ caiva), the field of activity (kṣetraṃ), the knower of that field (kṣetra-jñam eva ca), the nature of true knowledge itself (jñānaṃ), and the ultimate object that is to be known (jñeyaṃ ca).