One of the hallmarks of Hindu philosophy is its dialectical methodology—the philosophers are devoted to establishing their philosophical positions, but they treat the views of their opponents with respect. Several schools of philosophy have been existence for more than 2500 years and they have always had significant philosophical differences but each school formulates its arguments after listening to the arguments from the other schools. The dialectical method of philosophical discussion proceeds through three steps, namely Purvapaksa, Khandana, and Uttarapaksa. The philosopher begins by stating the views of his opponents—known as the Purvapaksa. After that he offers the refutation for the arguments of his opponents—known as the Khandana. Finally, he offers his own theory—known as the Uttarapaksa (in some texts Uttarapaksa is described as Siddhanta or conclusion).