胡適的一生之中，有過眾多的學生和朋友，但也有一些政治上和學術文化上的敵人。但無論是對政敵和學敵，胡適大都放不下「正人君子」的身分和「縉紳階級」(gentleman)的架子，而總會顯示出其寬厚、持平、講理、公道、彬彬有禮和不爲已甚的良好態度和修養。如果說，胡適對魯迅、梁漱溟、郭沫若等政敵學敵，確實秉持了「惡而知其美」的持平態度，但當他一面對自己的老學生馮友蘭，便好像變成了另一個人，不僅「惡而知其美」的持平態度不翼而飛，就連他平日頗爲自矜的「正人君子」的身分，還有那「縉紳階級」的架子，也可以因馮友蘭而一齊拋入汪洋大海。對馮友蘭的憎惡，已在胡適心中糾結成一團漆黑如墨的情結，幾乎是終生不可開解。胡適長時期對馮友蘭的種種苛責，與他一貧待人接物的溫良恭儉讓，構成了如許巨大的反差，這不僅使胡適的研究者咸感困惑，恐怕就連胡適自己一時間亦難以說清楚講明白。本文通過系統性地比對和剖析了胡適大量的日記、書信、文稿以及其它相關資料，把握了胡適心靈上鮮爲人知的另一面相，並鉤勒了胡適的「馮友蘭情結」的萌芽、形成和發展的曲折過程。本文認爲，胡適的馮友蘭情結，乃係緣於自己的《中國哲學史大網》被馮友蘭的《中國哲學史》超越和取代之後，又無力扳回一城而挑激起來的不情願不甘心再加上不服氣，以及隨之而來的痛楚失落懊惱和妒忌。

An American-educated liberal and a gentleman in the Western style, Hu Shi characteristically treated his political or intellectual opponents in a fair and graceful manner. But he turned overly harsh and even venomous when dealing with his onetime student Feng Youlan, as well as Feng's works. Scholars have always been intrigued by Hu's Feng Youlan complex. And it appears that even Hu Shi himself was sometimes bewildered about his own attitude toward Feng. This paper systematically examines relevant documents such as diaries, correspondence and manuscripts; attempts to delineate the formation and development of this complex; and sheds light on this dark aspect of Hu's character. It suggests that Hu's Outline of the History of Chinese Philosophy was surpassed and replaced by Feng's History of Chinese Philosophy, and this became a source of annoyance and frustration to Hu.