This paper explores the influence of the Aristotelian theory of science and the philosophical t dition of writing prolegomena upon a classical legal theory text. Through investigation of commentaries and glosses on preliminary topics in the introduction of Mukhta~ar al-Muntahā, an Islamic legal theory textbook, we will see how the conception and presentation of Islamic disciplines was influenced by the theory of science. The Aristotelian theory of science propounded that each scientific discipline comprises three elements: subject matter, principles, and problems. Meanwhile the philosophical tradition advocated for writing a proper prolegomenon, which included introducing a work with several preliminary topics, elucidating its subject matter and defining its purpose. The paper shows how these two influences, the Aristotelian theory of science and the tradition of writing prolegomenon, intersected in the commentaries and glosses on the initial section of a handbook of Islamic legal theory, the Mukhta~aral-Muntahā of Ibn al-Hājib (d. 646/1249), a prominent linguist and Maliki jurist. This text was subject to numerous commentaries and glosses. This paper will focus on those written around the fourteenth century, authored by notable figures such as Qādī Baydāwī (d. 691/1291-92), Diyāʾ al-Dīn al-Tusī (d. 706/1306-7), Qutb al-Dīn al-Shīrāzī (d. 710/1311), Jamāl al-Dīn al-Hillī (d. 726/1325), Badr al-Dīn al-Tustarī (d. 732/1332), Rukn al-Dīn al-Astarābādī (d. 715/1315), Shams al-Dīn al-Isfahānī (d. 749/1349), ʿAdud al-Dīn al-Ījī (d. 756/1355), Saʿd al-Dīn al-Taftāzānī (d. 792/1390) and al-Sayyid al-Sharīf al-Jurjānī (d. 816/1413). The analysis herein will focus on their discussion of two preliminary sentences, which reveal a tension between the notions of mabādiʾ as principles and mabādiʾ as beginnings, the former in relation to the theory of science and the latter in relation to the tradition of writing proper introductions. The paper demonstrates that Islamic legal theory was conceptualized and presented in accordance with the philosophical theory of science, as reflected in the commentaries on Ibn al-Hājib’s Mukhta~ar, and that it stimulated a new conception of mabādiʾ that encompasses both its literal and terminological meanings. Ultimately, the debates on this topic gave rise to an argument justifying knowing the aspect of unity of a science and a critique of the theory of science at that time, challenging the idea that the genuine elements of a science are three, asserting instead that they are one.