演繹法足以建構整個數學體系，何以大多數歷史學者對其解決歷史難題致以最深之疑惑？以演繹法治史出現截然相反的兩種結果。一種結果荒謬絕倫；一種結論正確無誤。何以同一方法會出現相反之結果？演繹法治史效驗如神之例證，是整個探究過程符合演繹法之原則；演繹法導致荒腔走板之結論肇因於探究過程外表似合演繹原則，實際則不然。總結演繹法治史之得失在於大前提正確，可對小前提做出正確判斷；大前提大體正確，亦有相當成效；大前提涉及片斷支節，有時可收攻錯之效；如果違逆演繹原則，結論往往流於荒謬。

A deduction system is suited to the task of actually constructing proofs in mathematics, but most historians believe the approaches adopted in mathematics are not capable to displaying arguments in problems of history. The reason is since the premises are not definite, no definite conclusion follows. Therefore, a deductive argument is an argument in which the conclusion is supported to follow the premises in such a way that it would be difficult to deny the truth of the conclusion in historical issues.