Agreeing with and being opposed to the philosophy have been common among Muslims since early Islam, and have been done in various scientific and conventional methods. In conventional and rhetoric confrontation, sometimes, we also see excommunication and accusation of exiting religion as well as not observing the apparent rituals of religious laws. One of the prominent examples in this arena is Ghazali. He is considered one of the most influential figures in the history of the Islamic thought, and his opposition to philosophy and philosophers is one of the most prominent aspects of his scientific and practical personality. He ardently pursued this opposition, both in the theoretical dimension through argumentative critique of the philosophers’ claims and in the mental and emotional dimensions in creating religious hatred towards philosophers. Ghazali’s theoretical discourse has been criticized and challenged frequently; however, the mental, rhetoric, polemic and conventional dimensions of his struggle have been neglected. This article investigates Ghazali’s confrontation with Avicenna, as the representative of the philosophical trend, by accusing him of weak faith, ignoring the religious law, and committing some sins such as drinking wine. Ghazali has done a field study in this regard, proving his claims about philosophers such as ignoring religious law, denying prophethood, considering their position higher than religious precepts, debauchery, hypocrisy, and the like. Now, the question is whether Ghazali’s method in that field study and proving those accusations on the prominent representatives of Islamic philosophy such as Avicenna and Farabi a scientific and logical method. The present study was done in a descriptive-analytical method with the aim of showing the level of validity of Ghazali’s method as well as stating its weak points and sophistries. The result of this study is that Ghazali’s method in his confrontation lacks scientific validity and his claim in this regard was not acceptable.