Adyayana Vidhi is an injunction enjoining Vedic studies. Traditionally, adhyayana is defined as committing the chosen Vedic texts to memory by repeating the teacher’s recitation. A student would live in the house of the teacher for a prescribed number of years.
Generally, there could be many who would like to study a text out of interest or curiosity. So the question is – why should there be a specific injunction prescribing its study? The discussion on this need of the injunction forms the first topic of the discussion of Mimamsasutra of Jaimini,where the purvapakshin (the school of opponents) suggests that the injunction refers to the need for committing the entire text to memory as Vedas are authority texts. The austerities prescribed to be followed during Vedic studies, too, would make sense as they are to be followed during the period of the Vedic study alone.
Mimamsakas opined that the injunction includes enquiry into the meaning of the texts. The texts must necessarily communicate certain ideas and it must not be claimed that the texts are studied just for punya (religious merit). Moreover, the import of these texts is to be known in order to perform the sacrifices prescribed in them properly. Hence, an analysis and enquiry of the text must be made in a systematic way.