We read in the Kathavallî 'The Person of the size of a thumb stands in
the middle of the Self, as lord of the past and the future, and
henceforward fears no more'; 'That Person of the size of a thumb is like
a light without smoke,' &c. (Ka. Up. II, 4, 1; 13). And 'The Person not
larger than a thumb, the inner Self, is always settled in the heart of
men' (Ka. Up. II, 6, 17). A doubt here arises whether the being measured
by the extent of a span be the individual soul or the highest Self.--The
Pûrvapakshin maintains the former view; for, he says, another scriptural
text also declares the individual soul to have that measure, 'the ruler
of the vital airs moves through his own works, of the size of a thumb,
brilliant like the sun, endowed with purposes and egoity' (Svet. Up. V,
7; 8). Moreover, the highest Self is not anywhere else, not even for the
purpose of meditation, represented as having the size of a thumb. It
thus being determined that the being of the length of a thumb is the
individual Self, we understand the term 'Lord,' which is applied to it,
as meaning that it is the Lord of the body, the sense-organs, the
objects and the instruments of fruition.--Of this view the Sûtra
disposes, maintaining that the being a thumb long can be none but the
highest Self, just on account of that term. For lordship over all things
past and future cannot possibly belong to the individual Self, which is
under the power of karman.--But how can the highest Self be said to have
the measure of a thumb?--On this point the next Sûtra satisfies us.