The sāttvika ego in generating the cognitive senses with limited powers for certain specified objects of sense only accounted for their developments from itself in accompaniment with the specific tanmātras. Thus
sāttvika ego + sound potential (śabda-tanmātra) = sense of hearing.
sāttvika ego + touch potential (śparś-tanmātra) = sense of touch.
sāttvika ego + sight potential (śrūpa-tanmātra) = sense of vision.
sāttvika ego + taste potential (vasa-tanmātra) = sense of taste.
sāttvika ego + smell potential (gandha-tanmātra) = sense of smell.
The conative sense of speech is developed in association with the sense of hearing; that of hand in association with the sense of touch; that of feet in association with the sense of vision; that of upastha in association with the sense of taste; that of pāyu in association with the sense of smell.
Last of all, the manas is developed from the ego without any co-operating or accompanying cause.
The Naiyāyikas, however, think that the senses are generated by the gross elements, the ear for example by ākāśa, the touch by air and so forth. But Lokācāryya in his Tattvatraya holds that the senses are not generated by gross matter but are rather sustained and strengthened by it.
There are others who think that the ego is the instrumental and that the gross elements are the material causes in the production of the senses.