We have seen that all systems of Hindu thought are connected together; and it is out of this interconnection, agreement and opposition that the ancients have constructed their sacred stories of Puranas and the Epics. We have seen that they conceived of eight principal energies of life the Heart as unmanifest; and Buddhi, Mind and the five elements as manifest. They also divided organic life into four kinds, the Viviparous, Oviparous, Trees, and Germs and in constructing their philosophical and sacred stories, they personified each idea, energy, as well as form of life into a Man or Woman, according as it represented Purusha or Prakrti, or a corresponding system of thought. This has the authority of the Upanishads and is the usual method with them.
Lunar Line of Kings: We have seen that the Mahabharata is a conflict of different systems of thought, which all meet in the region of the Mind. Hence, as the Moon is the presiding deity of the Mind, both the Kauravas and Pandavas, the principal combatants in the Epic, are described as belonging to the Lunar race; and even Krshna, the Supreme Purusha of Vedanta, is said to be of the same line.
Solar Link of Kings: In the Ramayana, on the other hand, we have the solar line of Kings, to which the prince of Ayodhya himself belongs; and here the problem assumes a slightly different form. As the Moon is the presiding deity of the Mind, even so is the Sun of Buddhi and so the Solar Line refers to the system of thought based on Buddhi and that is Yoga. As Yoga is really Vedanta-Yoga or half of Vedanta, Rama, the hero of Ramayana, is spoken of as but half an incarnation of Vishnu; while Krshna, who represents complete Vedanta, is said to be his perfect form. Thus, in the Ramayana we have Yoga, and its ally, Vaisesika, on the one hand; and Nyaya and Sankhya on the other; and Nyaya, based on Purushic Ether, is the common ground between them. The battle ground of the fight with Ravana is Lanka, which is significant of this idea; and the ten clays of battle between Rama and Ravana refer to the ten senses of knowledge and action associated with the idea of Purushic Ether and it is for this reason that this system is represented by this number. The question for decision is, is the Mind associated with all the ten senses of knowledge and action or with the senses of knowledge only? The former is the position of Vaisesika and Yoga, and the latter of Nyaya; and Rama has identified himself with the one, and Ravana, with the other. Hence the fight between them; in the Mahabharata the problem is rendered more intricate by the introduction of Vedanta; and Yoga, as its ally, is considered only as its first manifest form. Hence, while the apparent fight is between Yoga on the one hand, and Vaisesika and Nyaya combined on the other, and Vaisesika is the common ground between them, Yoga is conceived but as the outward form of Vedanta; which, in the person of Krshna, is its living and moving force. Hence, the real fight is between Vedanta on the one hand, and Vaisesika and Nyaya combined on the other; and between them too Vaisesika is the common ground.
Battle of Kurukshetra: And so the battle of Kurukshetra in fought on this common ground of Vaisesika, described as Dharma and it is for this reason that the very opening lines of the Bhagavad Gita commence with a reference to Dharma, which represents the Vaisesika system. The subject matter of the discussion is "Kuru", the imperative form of "Kri," meaning "to act" signifying the imperative necessity of Action; and so Dharmaksetra (field of Dharma) is coupled with Kurukshetra (field of Action) in the very first line of the Gita. The question to be debated is, Is Action necessary in the light of all systems of thought which meet on the common ground of Vaisesika, Vedanta and Yoga on the one hand, and Vaisesika and Nyaya and Sankhya on the other? The "battle" lasts for 18 days, because the question is to be decided by means of the knowledge of manifest life, in which Vedanta, based on the unmanifest energy of the Heart, is represented by Yoga; and so the fight is apparently between. Yoga on the one hand, and Vaisesika and Nyaya on the other, though Yoga may take such assistance from Vedanta, and Nyaya from Sankhya as they legitimately can. As Yoga, based on Buddhi, is represented by the number 7, and Vaisesika and Nyaya, based on Mind and Purushic Ether respectively, by 6 and 5, this makes a total of 18, corresponding to the 18 days of the battle of Kurukshetra.
Kauravas and Pandavas: Thus we see that the whole "Story" of the Mahabharata turns on a proper understanding of the character of the Mind; and in this story the Kauravas represent Nyaya, while the Pandavas Vaisesika; and the common ground between them is Nyaya; and this is the conflict of the Gambling Match. Then, as Vaisesika is the lower limit of Vedanta, the Pandavas slowly rise from Vaisesika to Yoga and thence to Vedanta. On the other hand, as Nyaya completes itself in Vaisesika, the Kauravas also rise from Nyaya to Vaisesika. Thus, in the second contest the Pandavas identify themselves with Vedanta and the Kauravas with Vaisesika; and Vaisesika is the common ground between them. This is the conflict of the second trial of strength, the battle of Kurukshetra.