A siddhanta wherein a fact is taken for granted, without investigation, and then proceeds the examination of its particular details, is called an Abhyupagama Siddhanta.<blockquote>अपरीक्षिताभ्युपगमात्तद्विशेषपरीक्षणं अभ्युपगमसिद्धान्तः॥३१॥ {अभ्युपगमसिद्धान्तलक्षणम्} (Nyay. Sutr. 1.1.31)<ref name=":4" /></blockquote>Vatsyayana Bhashya for the above sutra is as follows<blockquote>यत्र किंचिदर्थजातमपरीक्षितमभ्युपगम्यते अस्तु द्रव्यं शब्दः स तु नित्यो ऽथानित्य इति द्रव्यस्य सतो नित्यताऽनित्यता वा तद्विशेषः परीक्ष्यते सोऽभ्युपगमसिद्धान्तः स्वबुध्द्यतिशयचिख्यापयिषया परबुध्द्यवज्ञानाच्च प्रवर्ततइति। (Vats. Bhas. Nyay. Sutr. 1.1.31)<ref name=":5" /></blockquote>When a fact is taken for granted without investigation, such a siddhanta is called Abhyupagama or a Hypothetical Doctrine. Example, it is taken for granted, without investigation, that Sound is a substance and from that assumption proceeds an investigation as to whether Sound is eternal or non-eternal. In this investigation details of eternality or non-eternality of sound are examined. An author has recourse to this kind of Siddhanta with a view to display his intellect with an utter disregard for the intellect of others.(Page no 81 of Reference <ref name=":0" />)