[The Permissibility of Disagreement in Subsidiary Ijtihād-Based Issues]

Answer: The evidence for that is the saying of Allah the Exalted: “Allah does not burden any soul except with what it can bear.” [Al-Baqarah:286] If a mujtahid scholar researches, exhausts his examination and reflection, and his consideration and ijtihād lead him to a ruling, while another mujtahid’s ijtihād in the same issue leads him to a ruling contrary to that of the first mujtahid, then it is obligatory upon each of them to state what his consideration and ijtihād have led him to.
The error of one of them in reaching the correct ruling is an excused error, as indicated by the saying of Allah the Exalted: “And there is no blame upon you for that in which you have erred, but only for what your hearts intended.” [Al-Aḥzāb:5]
If it is said: Is it permissible for someone to claim that those who differ must abandon ijtihād in disputed issues and turn away from their ijtihād-based schools, given what is known of Allah’s condemnation of disagreement and those who differ in the Noble Qur’an, and given what is known that Allah the Exalted has perfected His religion in His Noble Book and upon the tongue of His trustworthy Messenger (May Allah bless him and his family and grant them peace)? And if Allah the Exalted had obligated His servants with the rulings that the mujtahids exerted themselves to obtain and over which disagreement occurred, He would have clarified them in His Book or upon the tongue of His Messenger (May Allah bless him and his family and grant them peace), as He clarified other subsidiary rulings explained in the Book or in the Sunnah?
It is said in reply — and from Allah is success — that what has been mentioned is not permissible. For events occur that necessitate ijtihād to obtain rulings for them.
An example of this is what occurred at the end of the days of the Companions: the birth of a child who possessed a sexual organ like that of a male and a sexual organ like that of a female, without any indicator that would give preference to his masculinity or femininity. There is no clarification in the Book of Allah the Exalted nor in the Sunnah of His Messenger (May Allah bless him and his family and grant them peace) regarding what share of inheritance this newborn deserves. If we were to say that ijtihād should be abandoned regarding the ruling of this case and refrain from addressing it, we would deprive him of inheritance — and it is not permissible to deprive the child of the deceased of inheritance.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.3