Mīmāmsa Sūtra 01.01.07

अस्थानात् ॥१-१-७॥

asthānāt ॥1-1-7॥

[अस्थानात् (asthānāt) - from not being situated in a stable place;]

(from not being situated.)

As it is not situated in a stable place, i.e. it does not persist.