शास्त्रार्थ = Dialectic reasoning, not Debate
The above as interpreted by self from a reading in Wikipedia. on Dialectics.
India is the founding place for this art whereby people attempt to discover truth of a subject matter.
The following taken from Wikipedia on topic :
Indian continental debate: an intra- and inter-Dharmic dialecticAnacker (2005: p. 20), in the introduction to his translation of seven works by Vasubandhu (fl. 4th c.), a famed dialectician of the Gupta Empire, contextualizes the prestige of dialectic and cut-throat debate in classical India and makes references to the possibly apocryphal story of the banishment of Moheyan post-debate with Kamalaśīla (fl. 713-763):
Philosophical debating was in classical India often a spectator-sport, much as contests of poetry-improvisation were in Germany in its High Middle Ages, and as they still are in the Telegu country today. The king himself was often the judge at these debates, and loss to an opponent could have serious consequences. To take an atrociously extreme example, when the Tamil Śaivite Ñānasambandar Nāyanār defeated the Jain ācāryas in Madurai before the Pāṇḍya King Māravarman Avaniśūlāmani (620-645) this debate is said to have resulted in the impalement of 8000 Jains, an event still celebrated in the Mīnāksi Temple of Madurai today. Usually, the results were not so drastic; they could mean formal recognition by the defeated side of the superiority of the winning party, forced conversions, or, as in the case of the Council of Lhasa, which was conducted by Indians, banishment of the losers.
 Brahmin/Vedic/Hindu dialecticWhile western philosophy traces dialectics to ancient greek thought of Socrates and Plato, the idea of tension between two opposing forces leading to synthesis is much older and present in Hindu Philosophy. Indian philosophy, for the most part subsumed within the Indian religions, has an ancient tradition of dialectic polemics. The two complements, "purusha" (the active cause) and the "prakriti" (the passive nature) brings everything into existence. They follow the "rta", the Dharma (Universal Law of Nature).
Perhaps, now I have hint to understand why i tend to be so argumentative or why so many arguments to establish the Dharma in every matter come up in my mind. It is perhaps cultural