This study discusses the treatise of Jalal al-Din Davvani (d. 908/1502) named Risala fi ta'rif 'ilm. This treatise criticizes a definition of knowledge adopted by some theologians in the late period (muta'akhkhirin). The definition of knowledge at issue consists of three components: Attribution, discernment, no possibility of contradiction. Knowledge is an attribute as a category and with this attribution, a discernment is obtained. As a result of this process knowledge is acquired and there should be no possibility of this knowledge to be inconsistent. Davvani examines eight possibilities of the definition on knowledge. In each of these eight possibilities a different problems arises. According to Davvani, the definition mentioned is problematic in all probability. Nonetheless, Davvani does not propose another definition of knowledge that can replace the definition of knowledge that he criticizes. This article represents the process of reaching the definition of knowledge stated in the history of theological thought. The definitions on knowledge made from the first period (al-mutaqaddimin) are summarized and the strengths and weaknesses of these definitions are explained. There are two main approaches regarding the nature of knowledge in Islamic thought: According to the first approach pioneered by Fakhr al-Din Razi (d. 606/1202), absolute knowledge is a priory (badihi) and undefinable. According to the second one, the nature of absolute knowledge is a posteriori (nazari) and definable. The first part of this article includes the definitions and criticisms of knowledge in Islamic thought. The second part discusses the claim of originality. In the second part, Davvani's treatise will be evaluated for the first time. According to the conclusion of the treatise, the definition made to find the essence of knowledge is unfounded in all respect. It is important to evaluate the treatise as a reflection of anti-essentialism in the history of Islamic thought. Most contemporary studies do not count this treatise among Davvani's works. In the biography book al-A'lam written by Khayr al-Din al-Zirikli (d. 1976), Risga fi ta'rif 'ilm is counted among the works of Davvani. In the introduction of more than one manuscript, the work is clearly attributed to Davvani. As a result of the double-sided research, it has been ensured that the work belongs to Davvani. However, in other two manuscripts containing the same treatise, the work is shown as belonging to an unknown person named Sairzada. But there is no information found about this person. This name seems more like a copyist (mustansth) than an author. Possibly, such a mistake occurred as a result of confusing the two names. Davvani's small volume treatise sheds light on the intellectual atmosphere and level of its period. The definition of knowledge mentioned in the classical theology book of 'Adud al-Din al-Iji (d. 756/1355) called al-Mawaqif is superior to other definitions of knowledge. Instead of this definition of knowledge, which is presented as perfect, Jurjani (d. 816/1413) preferred the definition of knowledge attributed to al-Maturidi (d. 333/944) in the Sharh al-Mawaqif. This preference has been accepted as an implicit criticism for future generations, including Davvani.