Ana ɗaukar Shafi'i a matsayin wanda ya fayyace ƙa'idodin istinbāṭ (cire hukunci daga nassoshi) ya kuma tsara su da ƙa'idodi gama-gari masu cikakken tsari. Saboda haka, shi ne ya kafa ilimin usūl al-fiqh (ƙa'idodin fiqhu), duk da cewa mutane da yawa sun zo bayansa waɗanda suka fi shi sanin usūl al-fiqh da ma'anoninsa. Fuqahā (malaman fiqhu) kafin al-Shafi'i suna yin ijtihādi ba tare da ƙayyadaddun ma'auni na ijtihādi ba. Maimakon haka, suna dogara ne da fahimtarsu game da ma'anonin Sharī'ah da manufar hukunce-hukuncen, burinsu, abin da nassoshi ke nunawa, da abin da manufofinsu (maqāṣid) suke nufi. Saboda gogewar waɗannan fuqahā a karatunsu na Sharī'ah da cikakken sanin harshen Larabci, sun iya sanin ma'anonin nassoshi da fahimtar burinsu (ghāyāt) da manufofinsu (maqāṣid). Suna daidaita ra'ayoyinta da manufofinta wajen cire hukunci daga nassoshi ba tare da wata ƙa'ida da aka rubuta ta ƙayyadaddun ma'auni ba. I, fuqahā kafin al-Shafi'i, tun zamanin Sahabbai da Tabi'ai da waɗanda suka biyo bayansu, sun yi magana a kan wasu batutuwan usūl al-fiqh, suna cire dalilai da kuma muhawara a kansu. Misali, an rawaito daga 'Ali ɗan Abi Ɗalib cewa ya yi magana game da mutlaq (wanda ba shi da iyaka), muqayyad (wanda aka iyakance), khāṣṣ (takamamme), 'āmm (gama-gari), nāsikh (mai soke hukunci) da mansūkh (wanda aka soke). Sai dai hakan bai kasance cikin tsari ko hanya ƙayyadaddu ba. Fuqahān da suka yi magana a kan wasu batutuwan usūl al-fiqh ba su mallaki ƙa'idodi gama-gari masu cikakken tsari da za su koma gare su don fahimtar ma'anar Sharī'ah ko sanin yadda za a yi muhawara da su ko a ba wani fifiko a kansu ba. Amma da al-Shafi'i ya zo, ya fitar da ilimin usūl al-fiqh, ya kuma kafa dokoki masu cikakken tsari da ake komawa gare su wajen sanin matakan dalilan Sharī'ah. Ya zama sananne ga mutane cewa al-Shafi'i ya tsara ilimin usul a cikin littafinsa mai suna al-Risala, littafin da ya shahara. Amma gaskiyar magana ita ce al-Risala ya ƙunshi wani ɓangare kawai na ilimin usul da al-Shafi'i ya tsara. Duk wanda ya duba littattafan al-Shafi'i zai ga cewa al-Risala ya ƙunshi wasu daga cikin batutuwan ilimin usul al-fiqh kawai, kuma bai ƙunshi dukkan tattaunawar al-Shafi'i a kan usul ba. Al-Shafi'i yana da wasu littattafai waɗanda suke ɗauke da tattaunawa (a kan usul) kamar Kitab Ibtal al-Istihsan da littafin Jamma' al-'ilm. Har ma a cikin littafin al-Umm, a cikin shafukansa akwai tattaunawa a kan ilimin usul. A cikin waɗannan ya ambaci ƙa'idodi masu faɗi a tsakanin ƙa'idodi dalla-dalla.

Shafi’i is considered to be the one who delineated the principles of deduction (usul al-istinbat) and regulated it with general comprehensive principles. Thus, he was the originator of the science of usul al-fiqh (principles of jurisprudence), even though many people came after him who were more knowledgeable about usul al-fiqh and its definitions. The Fuqaha (jurists) before al-Shafi’i used to perform Ijtihād without having defined parameters for Ijtihād, rather they used to depend on their understanding of the Sharī’ah meanings and purpose of the ahkām, their aims, whatever its texts point to and whatever its objectives (maqasid) indicated. Due to the experience of those Fuqaha (jurists) in their study of the Sharī’ah and their thorough familiarity with the Arabic language, it allowed them to be acquainted with their meanings and to comprehend their aims (ghayat) and objectives (maqasid). They used to reconcile its concepts and objectives in deducing rules from the texts without having any recorded defined parameters. Yes, the Fuqaha before al Shafi’i, from the time of Sahabah, Tabi’in and those after them used to deal with issues of usul al fiqh and educe and oppose (evidences). Such as the narration about ‘Ali b’ Abi Talib  that he spoke about the mutlaq (absolute), muqayyad (restricted), khas (specific), ‘aamm (general), nasikh (abrogator) and the mansukh (abrogated). However, that was not in a defined or set out manner. And those Fuqaha who dealt with certain issues of usul al-fiqh did not possess general and comprehensive principles to which they referred in order to understand the indication of the Sharī’ah or to know how to oppose or outweigh them. But when al-Shafi’i came he derived the science of usul al-fiqh and he laid down comprehensive laws to which reference was made in knowing the levels of the Sharī’ah evidences. It has become widely known to people that al Shafi’i set out the science of usul in his book entitled al-Risala, a work which is famous. But the reality is that the al-Risala contains only a portion of the science of usul outlined by al-Shafi’i. Anyone who examines the books of al-Shafi’i will find that al-Risala contains only some of the topics in the science of usul al-fiqh and it does not contain all of Shafi’i’s discussions on usul. Shafi’i has other books which contain discussions (on usul) such as The Book of the Refutation of Istihsan and the book Jamma’ al-’ilm. Even the book al-Umm within its pages there are discussion on the science of usul. In these he has mentioned comprehensive principles amidst the detailed rules.

Abin da ya taimaka wa al-Shafi’i wajen kafa ilimin usul shi ne cewa ya zo ne a lokacin da ilimin fiqhun Musulunci ya fara bunkasa sosai. A cikin ƙasashen Musulunci sai ƙungiyoyin malaman mujtahidai suka fara fitowa, suka fara samar da mazhabobi (makarantu). Muhawarar da ke tsakanin mujtahidai da masu goyon bayan mazhabobi ta ɗauki salo daban-daban a fannin fiqhu da dalilai. Saboda haka ya tsunduma cikin muhawara da waɗanda suka shiga wannan muhawara, kuma waɗannan tattaunawa su ne suka jagorance shi wajen tunani game da ƙa’idoji gabaɗaya kuma masu cikakken iko a matsayin ma’auni masu daidaita abubuwa, waɗanda ya kamata su zama tushen nazari da ƙarshe-ƙarshe. Ya haɗa waɗannan ƙa’idoji waje guda a matsayin jiki ɗaya na ilimi, wato ilimin usul al-fiqh. Abin mamaki game da usul ɗin al-Shafi’i shi ne yadda yake bi wajen tattauna usul ta hanyar shari’a, ba ta hanyar ma’ana ba. Ɗaya daga cikin manyan haɗari ga nazari, ma’ana ga farfaɗo da Ummah musamman a fiqhu da usul, shi ne hanyar ma’ana (logic). Al-Shafi’i ya nisanta kansa sarai daga hanyar ma’ana, ya kuma manne da hanyar shari’a. Ba ya sha’awar hanyoyin ka’idoji ko zato. Yana so ya daidaita al’amura na gaske da suke wanzuwa, watau ya ɗauki nassosin Shari’ah ya tsaya a iyakar nassin da kuma iyakar gaskiyar da nassin ya nuna, wadda mutane da kansu suke gani. Game da batun nasikh da mansukh (soke da wanda aka soke), ya kafa ƙa’idojin soke daga al’amuran da, a wurinsa, an tabbatar cewa suna ƙunshe da soke, waɗanda aka ɗauka daga abin da aka ambata a cikin ayar ko hadisin kansa, ko daga alamar soke (dalala), ko abin da aka ruwaito game da Manzon Allah ﷺ ta fuskar hadisai da ke nuna soke, ko duk abin da aka ruwaito game da Sahabban Manzon Allah ﷺ ta fuskar riwayoyi da hukunce-hukunce. Ba kamar yadda wasu da suka zo bayansa ba, waɗanda idan suka ga saɓani tsakanin ayoyi biyu ko hadisai biyu sai nan take su yi saurin cewa wani ya soke wani, har suka faɗa manyan kuskure. Sa'ad da al-Shafi'i ya zo da wata ƙa'ida, bai ɗauke ta daga wata muqaddima ta mantiqi ba, a'a, ya nuna asalan da ya samo ta daga gare su, ko dai daga wani hadisi na Manzon Allah ﷺ ko kuma daga fatawoyin Sahabbai. Hanyarsa wajen kafa ƙa'idojin ƙayyadaddun doka (qawa'id dabita) ta kasance ta aiki, inda ya dogara da gaskiyar al'amari, da hujjoji, da kuma amfani da waɗannan abubuwa a kan al'amura na zahiri. Abin da ya fi fitowa fili da usulun Shafi'i ya bambanta da shi shi ne cewa ya ƙunshi ƙa'idoji gabaɗaya na istinbadi (cire hukunce-hukunce), ba tare da la'akari da takamaiman hanyarsa ba. Ma'ana, usulinsa ya dace da kowace hanya, ko yaya bambancinta yake. Saboda haka, ma'auni ne da za a iya sanin ra'ayoyin da suke daidai da waɗanda ba su daidai ba da shi. Doka ce gabaɗaya wadda dole ne a bi ta a lokacin cire sababbin hukunce-hukunce, duk wata hanya da mutum ya zaɓa wa kansa, domin a auna ra'ayoyi da kuma daidaita cire hukunce-hukunce da doka gabaɗaya. Usulun al-Shafi'i ba a nufin ya zama usuli ga mazhabinsa kawai ba, duk da cewa mazhabin ya riƙe shi. Ba a rubuta shi don kare mazhabinsa da bayyana matsayinsa ba. A maimakon haka, ya ƙunshi ƙa'idoji gabaɗaya da cikakku na istinbadi (cire hukunce-hukunce). Manufarsa ba ta kasance karkata zuwa wani mazhabi na musamman ba, sai dai sha'awar daidaita hanyoyin ijtihadi da kafa iyakoki da jagorori ga mujtahidai. Ya kasance mai gaskiya a niyyarsa, kuma yana da fahimta daidai a lokacin da ya kafa ilimin usulul fiqhi, ta haka ya yi tasiri, ba tare da togiya ba, ga mujtahidai da malamai da suka zo bayan al-Shafi'i, ko sun yi adawa da ra'ayoyinsa ko sun goyi bayansu. Har zuwa lokacin, duk da bambancin salonsu, sun ga kansu suna bin hanyar da al-Shafi'i ya bi, wajen kafa ka'idoji gabaɗaya (qawa'id kulliyya) da gudanar da fiqh da istinbadi (fitar da hukunci) cikin tsari bisa dokoki gabaɗaya da ka'idoji na asali. Fiqh bayan sa ya zama an gina shi bisa tubalan da aka kafa, ba kamar tarin fatawoyi da hukunce-hukunce na kowane mutum (aqdiya) kamar yadda lamarin yake kafin sa. Ko da yake dukkan malamai suna bin sawun al-Shafi'i a fagen usul al-fiqh, amma hanyar da suka karɓi abin da al-Shafi'i ya kai ga cimmawa ta bambanta bisa ga salon fikihunsu daban-daban. Wasu sun bi ra'ayoyinsa, suka fara bayaninsu da faɗaɗa su, suka kuma saɓa da su, kamar mabiyan al-Shafi'i kansa. Wasu kuma sun karɓi mafi yawan abin da al-Shafi'i ya kawo, duk da cewa sun saɓa da wasu cikakkun bayanai na usul, amma ba jigon usul kansa ba. Tun da ba su saɓa ba game da jigo, tsari da hanyar usul na al-Shafi'i, kamar Hanafawa da waɗanda suka bi hanyarsu. Akwai kuma waɗanda suka saɓa wa al-Shafi'i a wannan usul, kamar Zahiriyya da Shi'a. Waɗanda suka bi al-Shafi'i a ra'ayoyinsa sun kasance Hanbaliyya. Sun karɓi usul na al-Shafi'i duk da cewa sun ce ijma'in da aka yarda da shi kawai shi ne na Sahabbai. Malikawan da suka zo bayan al-Shafi'i sun haɗa hanyarsu da yawancin abin da ke cikin usul na al-Shafi'i, duk da cewa sun ɗauki aikin mutanen Madina a matsayin hujja, kuma sun saɓa masa a wasu cikakkun bayanai. Amma waɗanda suka bi hanyarsa suka rungumi ra'ayoyinsa, su ne mabiya mazhabinsa, waɗanda suka himmatu sosai wajen ilimin usul al-fiqh kuma suka rubuta littattafai masu yawa a kansa. An waɗannan littattafai an rubuta su ne bisa tsarin al-Shafi'i a usul al-fiqh, waɗanda su ne ginshiƙai da tushen wannan ilimi, kuma har yau haka suke. Daga cikin manyan littattafai uku da aka sani cewa tsofaffi sun rubuta su: na farko, littafin al-Mu'tamad na Abu al-Husayn Muhammad ibn al-Basri (d. 413 H); na biyu, littafin al-Burhan na 'Abd al-Malik ibn 'Abd Allah al-Juwayni, wanda aka fi sani da Imam al-Haramayn (d. 478 H); na uku kuma, littafin al-Mustasfa na Abu Hamid al-Ghazali (d. 505 H). Bayan su ya zo Abu al-Husayn 'Ali, wanda aka fi sani da al-Amidi. Ya haɗa dukkan littattafan uku, ya kuma faɗaɗa su a littafinsa al-Ihkam fi usul al-ahkam, wanda ya kasance ɗaya daga cikin muhimman ayyuka da aka rubuta a kan usul al-fiqh. Amma waɗanda suka karɓi mafi yawan abin da al-Shafi'i ya kawo, kuma suka sha bamban da shi a wasu cikakkun bayanai, su ne Hanafawa. Hakan ya faru ne domin hanyarsu ta istinbat (cire hukunci) ta yi daidai da usul ɗin al-Shafi'i, duk da cewa hanyar da suka bi wajen ilimin usul ta samu tasiri daga furu' (rassan fiqhu). Sun yi nazarin ka'idojin usul ne domin su goyi bayan furu'. Don haka suka sanya furu' ya zama tushe; ƙa'idodin gabaɗaya kuwa an gina su ne a kansa, an kuma sanya su don su goyi bayansa. Watakila abin da ya ja hankalinsu zuwa wannan hanya shi ne cewa nazarinsu na usul an yi shi ne domin tallafa wa mazhabarsu, ba domin samar da ka'idoji da makarantarsu za ta cire hukunce-hukunce bisa su ba. Hakan kuwa saboda Abu Hanifa, wanda ya riga al-Shafi'i, ya rasu a shekarar da aka haifi al-Shafi'i. Hukunce-hukuncensa kuma ba su kasance bisa ƙa'idodi na gabaɗaya ba. Haka nan bayansa ya zo almajiransa Abu Yusuf, Muhammad da Zufar. Ba su damu da rubuta game da usul al-fiqh ba, sai dai ya rataya ga malaman mazhabar Hanafi daga baya su bi sawun cire ka'idoji da za su yi wa furu'in mazhabar Hanafi hidima. Ka'idojin sun zo ne bayan furu'in, ba su riga shi ba. Duk da haka, usul ɗin Hanafiyya gaba ɗaya an ciro shi ne daga usul ɗin Al-Shafi'i. Abin da suka saɓa da Shafi'iyya a kai kuwa shi ne batun cewa al-'aam (gama-gari) yana da tabbas (qat'i) kamar al-khaas (keɓaɓɓe).

da kuma babu tarjeeh (fifita wani ra'ayi akan wani) saboda yawan masu ruwaya. Waɗannan batutuwa ne na cikakkun bayanai, ba ka'idoji na gaba ɗaya ba. Saboda haka, ana iya ɗaukar usul ɗin Hanafi da na Shafi'i a matsayin usul guda ɗaya ga fiqhu. Hanyarsu wajen furu' da sabanin da ke cikin wasu cikakkun bayanai ba wani usul daban ba ne, amma suna da usul guda ɗaya dangane da cikarsa, faɗinsa da ka'idodinsa. Kusan ba za ka taɓa ganin bambanci tsakanin littafi na usul Shafi'i da littafi na usul Hanafi ba. Maimakon haka, dukansu nazari ne na ka'idoji (usul) iri ɗaya na fiqhu. Ɗaya daga cikin mafi muhimmancin littattafan usul ga Hanafawa shi ne Usul al-Bazdawi, wanda Fakhr al-Islam 'Ali ibn Muhammad al-Bazdawi (d. 483 H.) ya tsara.

and that there is no tarjeeh (outweighing) due to the great number of transmitters. These are detailed issues and not comprehensive principles. That is why it is possible to consider the Hanafi and Shafi’i usuls as one usul for fiqh. Its approach towards the furu’ and disagreements in certain details is not another usul but they are one usul in its comprehensivity, generality and principles. You hardly ever see any difference between a book in shafi’i usul and a book in Hanafi usul. Rather, all of them are a study of the same principles (usul) of fiqh. One of the most important books of usul for the Hanafis is the usul al-Bazdawi compiled by Fakhr al-Islam ‘Ali ibn Muhammad al-Bazdawi (d.483 A.H.)

Waɗanda suka saɓa wa al-Shafi’i a cikin usulinsa, su ne Zahiriyya da Shi’a. Sun saɓa wa usulin al-Shafi’i a wasu abubuwa masu muhimmanci na asali, ba a cikin cikakkun bayanai kawai ba. Dangane da Zahiriyya, sun ƙi Qiyas (ƙiyasi ta hanyar hukunci) gaba ɗaya, kuma sun dogara ne kawai da ma’ana ta zahiri ta nassoshi. Har ma abin da ake kira qiyas jali (ƙiyasi bayyananne) ba su ɗauke shi a matsayin wani ɓangare na Qiyas ba, sai dai a matsayin nassi. Kulawarsu ga nassi ba komai ba ne face kulawa ga ma’anar zahirin nassin. Shugaban wannan mazhaba shi ne Abu Sulaiman Dawud ibn Khalaf al-Isfahani (ya rasu a shekara ta 270 bayan hijira). Ya kasance daga cikin Shafi’iyya. Ya koyi fiqhu daga almajiran al-Shafi’i. Sai ya bar mazhabar al-Shafi’i ya zaɓi wata mazhaba ta musamman domin kansa, inda zai dogara ga nassi kawai. Ana kiran ta mazhabar Zahiriyya (masu bin zahiri). Ibn Hazm yana cikin su. Wasu mutane ne suka sa shi ya shahara, suka yi masa kwatancin ɗaukaka har mutane suka fara sha’awar littattafansa, duk da cewa su littattafan fiqhu da sauran usulai sun fi nasa a fannin tattaunawar fiqhu da kuma hanyar fitar da dalilai. Dangane da Shi’a, sun saɓa wa usulin al-Shafi’i ta hanya mai girma, domin sun maida maganganun imamansu hujja ta Shari’a kamar Alƙur’ani da Sunnah. A gare su, hujja ce da take biye da hujjar Alƙur’ani da ta Sunnah aƙalla. Sun halatta maganar imamai ta takaita Sunnah. Suna cewa:

As for those who disagreed with al-Shafi’i in his usul, they are the Zahiris and Shi’a. They disagreed with al-Shafi’is usul in some of its basic elements and not just in the details. As for the Zahiris, they completely rejected Qiyas (analogical deduction) and depended solely on the apparent (zahir) (meaning) of the texts. Even what is termed as the qiyas jali (clear analogy) was not consider as a part of Qiyas but as text. Their consideration of the text is nothing other than a consideration of the apparent (zahir) (meaning) of the text. The imam of this mazhab is Abu Sulayman Dawud ibn Khalaf al-Isfahani (d.270 A.H.) He was from the Shafi’iyya. He learnt fiqh from the students of al-Shafi’i. Then he left the mazhab of al-Shafi’i and chose a special mazhab for himself where he would only rely on the text. It is called the Zahiri mazhab (literalists). Ibn Hazm is one of them. Certain people made him popular and gave a glowing description about him until people became interested in his books even though they were below the level of the books of fiqh and other usuls in terms of the jurisprudential discussion and angle of educing evidences. As for the Shi’a, they disagreed with al-Shafi’is usul in a significant way for they made the sayings of their imams a Sharī’ah dalīl like the Qur’ān and Sunnah. For them it is considered a proof which follows the proof of the Qur’ān and that of the Sunnah at the very least. They permitted the speech of the imams to specify the Sunnah. They say:

Shī'ar Imāmiyya suna sanya Imamansu a matsayi kusa da Sunnah. Ijtihadi a wurinsu an takaita shi ga mazhaba, ba a yarda mujtahidi ya yi ijtihadi da abin da ya saba wa ra'ayoyin mazhaba ba, wato ba a yarda mujtahidi ya yi ijtihadi da abin da ya saba wa maganganun Imam al-Sadiq ba. Sun ki karbar hadisai sai dai idan sun zo ta hanyar Imamansu. Ba sa karbar Qiyas. An ruwaito a jere (tawatur) daga Imamansu, kamar yadda suka ruwaito a cikin littattafansu, cewa idan aka yi qiyasi a kan Shari'a, to addini yana lalacewa.

The Imami Shi’as place their Imams in a position close to the Sunnah. Ijtihād for them is restricted to the mazhab, it is not permitted for the mujtahid to contradict the views of the mazhab i.e, it is not permitted for the mujtahid to make Ijtihād with what contradicts the sayings of the Imam al Sadiq. They rejected ahadīth except if it came via their imams. They do not take Qiyas. It has been recurrently reported (tawatara) about their imams as they have narrated in their books that when analogy is made to the Sharī’ah the deen is destroyed.

Wannan shi ne halin ci gaban ilimin usul al-fiqh bayan al-Shafi'i ta fuskar yarda ko adawa da shi a wajen malaman Musulunci. Dangane da ilimin kansa, bayan al-Shafi'i an tattauna shi sosai, kuma ya samu masu sharhi da marubuta da yawa. Abin mamaki ne cewa a zamanin da suka biyo bayan zamanin al-Shafi'i, ijtihadi ya ragu, mujtahidai sun yi karanci, kuma a zamanin da suka biyo bayan wancan zamani aka rufe kofar ijtihadi. Duk da haka, ilimin usul al-fiqh ya bunkasa ya yi fure, bincike game da ka'idojinsa ya karu, kuma al'amuransa sun zama masu zurfi da tsayin daka. Amma duk wannan ta fuskar ka'ida ta ilimi ne, ba ta fuskar aiki ba. Saboda haka, ba ta yi tasiri ba wajen samar da mujtahidai, ko karya zaton cewa an rufe kofar ijtihadi, ko kawo karshen wannan zato. Watakila dalilin hakan shi ne usul al-fiqh a wadancan zamuna na baya ya dauki hanya ta zalla ta ilimi, inda tattaunawar ka'ida ta yi galaba, aka kuma saka cikinsa karatuttukan da ba su da alaka da usul al-fiqh. Hankalin masu bincike ya karkata zuwa ga nazari da gyara ka'idojin da ke goyon bayansu da hujjoji, da zabar wadda ke da hujja mafi karfi, ba tare da la'akari da ko akwai wata hakika a bayanta ba. Zato na ka'ida ya yawaita, suka yi nazari kan dalala (ma'anonin nassi) suka rarraba ta bisa rarrabuwar malaman mantiq (ilimin hankali). Suka tayar da muhawarorin da ba su da alaka da usul al-fiqh, kamar husn (kyau) da qubh (muni), shin su na hankali ne ko na shari'a? Ko kuma tambayoyi kamar: shin godiya (shukr) ga mai ni'ima wajibi ne saboda shari'a ko saboda hankali? Suka kirkiro karatuttukan da suka fito daga ilmin Kalam (ilimin tauhidi na falsafa) ba daga usul al-fiqh ba, kamar batun kasancewar annabawa ba su yi kuskure ba, da kuma halascin annabawa su yi kuskure ko mantuwa a al'amuran da suka shafi isar da Sako. Sun yi nazari da suka shafi harshen Larabci, ba ga usul al-fiqh ba. Sun yi nazari a kan asalin harsuna, kuma sun yi nazari a kan huruf da asma. Ta haka ne suka sa ilimin usul al-fiqh ya zama mai tsauri, suka mayar da shi daga bangarensa na shari'a zuwa nazari na ka'ida da falsafa, wanda malami ba zai iya cire mafi sauki daga cikin hukunce-hukunce ba. Har ya kai ga kusan an rasa amfaninsa, babu wani tasiri a cikin shari'a ko wajen cire hukunce-hukunce (istinbat). Tun da ilimin usul al-fiqh yana da muhimmanci sosai wajen cire hukunce-hukunce da bunkasar bangaren shari'a, shi ya sa wajibi ne a kula da nazarin usul al-fiqh a matsayin nazari wanda ya dogara da zahiri ba ka'ida kawai ba. Ya isa a yi nazarin da ya shafi cire hukunce-hukunce, wanda ake karatunsa tare da dalilai masu nuna hukunce-hukuncen da kuma al'amuran da suka dace da ma'anoninsu, har a samar da mujtahidai, a kuma samu dukiyar shari'a da za ta magance sababbin al'amuran da ke tasowa kullum a duniyar Musulunci da sauran duniya.