I just read a very nice article by Francis X. Clooney which nicely captures, in my view, the down-to-earth attitude of Mīmāṃsā authors towards the sacrifice (and any other matter). Just an excerpt of it:
In general Jaimini describes the sacrifice without mythological and cosmological references. He uses words like prakṛti-vikṛti (archetype-ectype), pradhāna-guṇa (primary element-qualification), nāma-rūpa (name form) and dharma in outlining his structure of the sacrifice, words used elsewhere, in systems such as the Vaiśeṣika or Sāṃkhya, with cosmological reference. But he makes no such reference; he claims the words as his own but uses them with limited, particular and ritual and grammatical senses. In general, the world is merely loka: that neutral place whence elements of the sacrifice come. It is the realm of what merely is, where things are religiously indifferent or only potentially relevant before being introduced into the sacrifice.(Clooney 1986:203)
I only disagree with Clooney when he refers to Jaimini as if he were ignoring the philosophical implications of these terms. In fact, he was probably justified in ignoring it, since the sacrificial meaning is probably the older one. The same applies even to pramāṇa, which is used until today in Mīmāṃsā in its pristine meaning of "instrument for knowing" a certain thing (such as, the application of a certain sacrificial detail), with no further epistemological implication. Mīmāṃsā authors use a terminology driven out of ritual exegesis (what later crystallised into the Śrautasūtras), which is one of the oldest fields of investigation in India.