Shaykh Muhammad Hasan Hitu (Allah preserve him) is a contemporary scholar of legal methodology with a number of published works on the subject. I’m currently working on translating one of his short works. Here’s an excerpt from the beginning of the book that explains how the discipline of usul al-fiqh developed. Enjoy!

The discipline of legal methodology (usul al-fiqh) that we study today was not known in its present form at the beginning of Islam. Early Muslims—the Companions, the Followers, and others who lived during the early Islamic period—had no need for its principles because they possessed a sound language faculty that enabled them to grasp all the interpretive principles that derive from the Arabic language.

Just as they knew by second-nature that the doer of a verb (fa`il) should be in the raf` state, they knew by second nature that the word ma was coined to indicate generality, and that it is used literally for non-rational beings and figuratively for rational ones. The same is said of all methodological principles that derive from the Arabic language.

What is said of their innate knowledge of its language-related principles may also be said of their innate knowledge of its other principles. They knew by second-nature, for example, that scholarly consensus and analogy constitute legislative proof.

As for the methodological principles that relate to hadith-transmission—such as the identification of defects in chains of transmission or in the textual variants of various hadiths—they had no need for them because there was no intermediary between them and the Messenger of Allah (Allah bless him and give him peace). They were legally bound to implement whatever they heard from him without any disagreement or dispute.

When the Islamic dominions expanded, and the language faculty weakened, the need arose for scholars to document the methodological principles that derived from it. And when the distance between the Prophet (Allah bless him and give him peace) and the succeeding Muslim generations grew long, and hadiths began to be transmitted through narrators, the need arose for scholars to document the methods of investigating the acceptability of hadith narrators and distinguishing a genuine hadiths from fake ones. All these are the methodological principles that relate to the sunna and they later evolved to become their own independent discipline, hadith methodology.

All of the above may be said of the remaining topics of legal methodology, just as it may be said of all the religious disciplines that were invented after the passage of the early Islamic period.

(Shaykh Muhammad Hasan Hitu, al-Khulasa fi Usul al-Fiqh, Kuwait: Dar al-Diya (2005), pp. 1–2)