Vācaspati was a Maithili Brahmin who lived near the frontier between India and Nepal (what is now Vachaspati Nagar (Andhra Thardhi), Madhubani). The details of his life have been lost, though he is said to have named one of his works after his wife, Bhāmatī. He wrote commentaries on the main works of all the major Hindu schools of thought at the time, as well as one non-commentary, Tattvabindu.
In Tattvabindu, Vācaspati examines four competing theories of linguistic meaning:
Mandana Misra's (sphoṭavāda), which involves grasping the meaning of a word or sentence by perceiving a sphoṭa or single holistic sound, which is distinct from the elements (sounds or characters) that make up the word or sentence;
the Nyāya theory which involves concatenating the memory traces (saṃskāra) of momentary components of a word or sentence when we hear the final momentary component;
the similar Mīmāmsā theory, according to which our grasp of the meaning of a sentence lies in the memory traces created by the words; and
the Prābhākara Mīmāmsā theory, anvitābhidhānavāda, according to which the meaning of a sentence is derived from the meanings of its words, each of which has an individual meaning in the sentence as well as having syntactic relations with the other words — no sphoṭa or memory traces are required.
After examining each of these theories, Vācaspati presents his own theory, abhihitānvayavāda, according to which understanding of the meaning of a whole sentence is reached by inferring it, in a separate act of lakṣanā or implication, from the individual meanings of the constituent words.