Kadızâde-i Rumî

Mathematician and astronomer (B. ? – D. After 1440). He was from a family who educated scientists. He was referred as Kadızâde because it was his grandfather Kadı Mahmut Çelebi who raised him after the death of his father. He was also known as Musa Paşa or Musa Çelebi. He studied religious and mental sciences under the Molla Fenarî and his grandfather. Later, he went to Konya together with Şeyh Bedreddin, who was one of the students of his grandfather, and he took astronomy lessons from Müneccim Feyzullah. One of his teachers in Anatolia was Saferşah er-Rumî. Despite the objections of his family, he went to the region of Transoxiana and Khorasan in the beginning of the 1400s, with the encouragement of his teacher Molla Fenâri. Starting from 1411, he attended the lessons of the Islamic theologian and mathematician Seyyid Şerif el-Cürcanî, who was one of the leading scientists of the period in Samarkand. However, it is known that he conflicted with his teacher later on because his teacher looked at everything with the eye of a mathematician, and he left the lessons and criticized various thoughts written in Şerhu’l-Mevakıf that was the famous work of his teacher.

Kadızâde, who met Ulugh Beg in Samarkand, became his private teacher. After that, he was assigned as the principle hodja in the Uluğ Bey Madrasah and was assigned as the chief of the Samarkand Observatory after Cemşid el-Kâşî. Ulugh Beg and other teachers participated in the lessons of Kadızâde. Kadızâde gave big importance to scientific autonomy. He resigned from giving lessons because Ulugh Beg discharged one teacher without his notice. When he asked the reason why, he gave the following answer to Ulugh Beg: “I took on a task upon a recommendation, a task in which dismissal is not in question. I thought that teaching would be like this until now. However, since I’ve seen that dismissal is also implemented in this work, I resign from this job”. Upon this, Ulugh Beg took back the relevant teacher to duty.

The impact of the students he educated has not yet been totally put forward in the region of Central Asia Islamic – Turkish and Iran culture. However, he inculcated his students to go to the Ottoman country. When Ali Kuşçu and Fethullan Şirvanî came to Anatolia with his inducement, they also brought the rich accumulation of the school of astronomy and mathematics of Samarkand together with them. By this way, even though Kadızâde realized his scientific works in another geographic region, he served his original motherland through his students. For this reason, Taşköprüzâde Ahmed Efendi placed him in the second level of the Ottoman ulama. Besides, the work named Şerhu Eşkâ-li’t-tesîs of Kadızâde about geometry and his work named Şerhu’l-Mülahhaş fî ilmi’l-heye about astronomy were read as school books in the secondary level of Ottoman madrasahs. By this way, Kadızâde, who enriched and orientated the Ottoman science life both with his students and with his works, is regarded as the first original mathematician and astronomer educated in the Ottoman science environment.

There isn’t more information about the works of Kadızâde Rumî in Samarkand. His date of death is also not precisely known but the date of 1412 is mentioned in various encyclopedias, which was probably derived from the information of Abdülhak Adnan Adıvar can be found. However, the fact that the certificate of proficiency (diploma) that he gave to his student Fethullah eş-Şirvanî was dated as 13^th September 1440 proves that he was alive on this date.

In the summary of the explanation he wrote for the work of Çağminî, Kadızâde objected to the approach of Çağminî about astronomy. According to Kadızâde, only the situation that the world was a globe can be investigated among physical entities. The opinions about this topic change from researcher to researcher. Besides, the final goal of astronomy is to investigate celestial bodies; therefore, it is not correct to deal with the earth. From the following sentence he used in the presentation of his work named Şerhu’l-Mülahhaş fî ilmi’I-hey’e “In our days, among the foundations educating sciences related to the truth and the foundations related to exercise, especially the mathematical foundations are rooted out”, it is understood that he was rather uncomfortable with the astronomy ideology of Ibn Heysem that created a synthesis (analysis) of the physician and mathematician opinions represented by the works of Nasirüddin-i Tûsî. This attitude of Kadızâde became clearer with the fact that his student Ali Kuşçu tried to eliminate the ideology of İbnü’l-Heysem in his books named er-Risâletü’l-fethiyye fî ilmi’l-hey’e and Şerhu’t-Tecrîd and it is seen that these two scientists completed each other. As a matter of fact, these works were read together in the Ottoman madrasahs.

MAIN WORKS:

MATHEMATICS: Tuhfetü'r-re îs fî şerhi Eşkâli't-te'sîs (explanation of the work named Eşkâlü't-tesîs of Şemseddin Muhammed b. Eşref es-Semerkandî), Risale fi'stih-râci ceybi derece vâhide bi-amâlin müessese alâ kavaide hisâbiyye ve hendesiyye alâ tarîkati Gıyâşiddîn el-Kâşî (Explanation of the paper of Cemşîd el-Kâşî concerning the method of algebra. The most original work written by Kadızâde in the field of mathematics), Haşiye 'ulâ Tahrîri usûli'l-hendese (An annotation written for the Tahrî-rü'l-uşûl fî ilmi'l-hendese of Tûsî).

 ASTRONOMY: Şerhu'l-Mülahhaş fî ilmi'l-hey'e (The explanation of the el-Mülahhaş fi'l-hey'e of Çağmînî. It is presented to Ulugh Beg. It is the most important work that Kadı­zâde wrote in the field of theoretical astronomy. It was read in Ottoman madrasas as a secondary level school book), Hâşiye ala Tahrîri'l-Mecistî (An annotation explaining some difficult parts of the explanation named Tabîrü't-Tahrîr written by Nizâmeddin en-Nîşâbûrî for the work of Nasîrüddîn-i Tûsî named Tahrîrü'l-Mecistî), Risâle fi'stihrâci hatti nışfi'n-nehâr ve semti'l-kıble (the astronomy work of Kadızâde written in Persian).  

   REFERENCE: Sâlih Zeki / Âsâr-ı Bâkiye (s.133-139, 186-190, 1911), Abdülhak Adnan Adıvar / Osmanlı Türklerinde İlim (s. 16, 1970), A. Süheyl Ünver / Bursalı Kadı Zâde Rumî ve Devrinin Bilimcileri (İzmir 1970), Cevat İzgi / Osmanlı Medrese­lerinde İlim (I, 275-285, 370-388, 1997), Cemil Akpınar / Osmanlı Astronomi Literatürü Tarih ( c. I s. 5-21; 1997), Ekmeleddin İhsanoğlu / Osmanlı Matematik Literatürü Tarihi (2 cilt, Ramazan Şeşen ve Cevat İzgi ile, 1999),  TDV İslâm Ansiklopedisi (c. 24, 2001), İhsan Işık / Ünlü Bilim Adamları (Türkiye Ünlüleri Ansiklopedisi, C. 2, 2013) - Encyclopedia of Turkey’s Famous People (2013).