“But like the senses the tanmātras are also special modifications of the ahaṃkāra having specially modified characteristics such as sound, touch, etc., why, therefore, are they not mentioned as special modifications (_viśeshas_)? The answer is that those only are mentioned as special modification which are ultimate special modifications. The tanmātras are indeed the special modifications of the ego, but they themselves produce further special modifications, the bhūtas. The aviśeshas are explained as the six aviśeshas. The tanmātras are generated from the tāmasa ahaṃkāra gradually through sound, etc. The category of mahat which is the ground of all modifications, called also the buddhi, has six evolutionary products called the aviśeshas. Though the mahat and the prakṛti may also be regarded as the root-causes out of which the tanmātras have evolved, yet the word aviśesha is used as a technical term having a special application to the six aviśeshas only.” The modifications of these are from the buddhi through the intermediate stage of the ahaṃkāra, as has been explained in the _Bhāshya_, I. 45. Thus we see that the _Yoga-vārttika_ says that the _Bhāshya_ is here describing the modifications of buddhi in two distinct classes, the aviśeshas and the viśeshas; and that the mahat has been spoken of as the source of all the aviśeshas, the five tanmātras and the ego; strictly speaking, however, the genesis of the tanmātras from mahat takes place through the ego and in association with the ego, for it has been so described in the _Bhāshya_, I. 45. Nāgeśa in explaining this _Bhāshya_ only repeats the view of _Yoga-vārttika_. Now let us refer to the _Bhāshya_ of I. 45, alluded to by the _Yoga-vārttika_: “The gradual series of subtler causes proceeds up to the aliṅga or the prakṛti. The earth atom has the smell tanmātra as its subtle cause; the water atom has the taste tanmātra; the air atom the touch tanmātra; the ākāśa atom the sound tanmātra; and of these ahaṃkāra is the subtle cause; and of this the mahat is the subtle cause.” Here by subtle cause (_sūkshma_) it is upādānakāraṇa or material cause which is meant; so the _Bhāshya_ further says: “It is true that purusha is the subtlest of all. But yet as prakṛti is subtler than the mahat, it is not in that sense that purusha is subtler than prakṛti for purusha is only an instrumental cause of the evolution of mahat, but not its material cause.” I believe it is quite clear that ahaṃkāra is spoken of here as the _sūkshma anvayikārana_ of the tanmātras. This anvayikāraṇa is the same as upādāna (material cause) as Vācaspati calls it. Now again in the _Bhāshya_ of the same _sūtra_ II. 19 later on we see the liṅga or the mahat is the stage next to prakṛti, it is differentiated from it though still remaining integrated in the regular order of evolution. The six aviśeshas are again differentiated while still remaining integrated in the mahat in the order of evolution (_pariṇāmakramaniyama_).