Samana evam chabhedat III.3.19 (378)

In the same (Sakha also) it is thus (i.e., there is unity of Vidya,) owing to non-difference (of the object of meditation).

Samana: in the same Sakha; Evam: every, (it is) like this; Cha: and, also; Abhedat: owing to non-difference.

A corollary to Sutra 5 is proved.

In the Agnirahasya in the Vajasaneyi Sakha there is a Vidya called Sandilya Vidya, in which occurs the passage "Let him meditate on the Self which consists of mind, which has the Prana for its body, and light for its form" (Sat. Br. Madhy. 10.6.3.2). Again, in the Brihadaranyaka (V.10.6) which belongs to the same Sakha we have "That person consisting of mind, whose being is light, is within the heart, small like a grain of rice or barley. He is the ruler of all, the Lord of all - He rules all this whatsoever exists."

A doubt here presents itself whether these two passages are to be taken as one Vidya in which the particulars mentioned in either text are to be combined or not. Are they one Vidya or different Vidyas?

This Sutra declares that, they are one Vidya, as the object of meditation (Upasya) is the same in both. The object of meditation in both is the Self consisting of mind. The combining of the particulars of a similar Vidya in the same Sakha is the same as in the case of such Vidyas which occur in different Sakhas. Although the two passages belong to one and the same Sakha, they yet constitute the Vidya only and their particulars have to be combined into one whole. The former directs worship, by means of such Vidya. The latter gives its Gunas (features).

Though there is some difference in minor details, the two descriptions of the Sandilya Vidya in the two Srutis are practically the same. So, a particular point mentioned in one Sruti in connection with the Sandilya Vidya has to be incorporated with the other, if it be not mentioned in the latter.

Therefore the Sandilya Vidya is one.