सर्गाणामादिरन्तश्च मध्यं चैवाहमर्जुन।अध्यात्मविद्या विद्यानां वादः प्रवदतामहम् ॥

I am the metaphysics among all sciences. I am knowledge of the Self among all branches of knowledge. I am the argument of dators. I am the logic of disputants. I am the speech of orators.In verse 20 above the Lord says, I am the beginning, the middle and the end of the whole movable and immovable creation. Here the whole creation in general is referred to.As the knowledge of the Self leads to the attainment of the final beatitude of life or salvation, it is the chief among all branches of knowledge.Pravadatam By the word controversialists, we should here understand the various kinds of people using various kinds of argumentation in logic such as Vada, Jalpa and Vitanda. Yada is a way of arguing by which one gets at the truth of a certain question. The aspirants who are free from RagaDvesha and jealousy raise amongst themselves questions and answers and enter into discussions on philosophical problems in order to ascertain and understand the nature of the Truth. They do not argue in order to gain victory over one another. This is Vada. Jalpa is wrangling in which one asserts his own opinion and refutes that of his opponent. Vitanda is idle carping at the arguments of ones opponents. No attempt is made to establish the other side of the question. In Jalpa and Vitanda one tries to defeat another. There is desire for victory.