The other tendency, namely that of tamas, has to be helped by the liberated rajas of aha@mkâra, in order to make itself preponderant, and this state in which the tamas succeeds in overcoming the sattva side which was so preponderant in the buddhi, is called _bhûtâdi._ From this bhûtâdi with the help of rajas are generated the _tanmâtras,_ the immediately preceding causes of the gross elements. The bhûtâdi thus represents only the intermediate stage through which the differentiations and regroupings of tamas reals in the mahat proceed for the generation of the tanmâtras. There has been some controversy between Sâ@mkhya and Yoga as to whether the tanmâtras are generated from the mahat or from aha@mkâra. The situation becomes intelligible if we remember that evolution here does not mean coming out or emanation, but increasing differentiation in integration within the evolving whole. Thus the regroupings of tamas reals marks the differentiation which takes place within the mahat but through its stage as bhûtâdi. Bhûtâdi is absolutely homogeneous and inert, devoid of all physical and chemical characters except quantum or mass. The second stadium tanmâtra represents subtle matter, vibratory, impingent, radiant, instinct with potential energy. These "potentials" arise from the unequal aggregation of the original mass-units in different proportions and collocations with an unequal distribution of the original energy (_rajas_). The tanmâtras possess something more than quantum of mass and energy; they possess physical characters, some of them penetrability, others powers of impact or pressure, others radiant heat, others again capability of viscous and cohesive attraction [Footnote ref. 2]. In intimate relation with those physical characters they also possess the potentials of the energies represented by sound, touch, colour, taste, and smell; but, being subtle matter, they are devoid ____________________________________________________________________ [Footnote 1: I have accepted in this section and in the next many of the translations of Sanskrit terms and expressions of Dr Seal and am largely indebted to him for his illuminating exposition of this subject as given in Ray's _Hindu Chemistry._ The credit of explaining Sâ@mkhya physics, in the light of the text belongs entirely to him.] [Footnote 2: Dr Seal's _Positive Sciences of the Ancient Hindus_.] 252 of the peculiar forms which these "potentials" assume in particles of gross matter like the atoms and their aggregates. In other words, the potentials lodged in subtle matter must undergo peculiar transformations by new groupings or collocations before they can act as sensory stimuli as gross matter, though in the minutest particles thereof the sensory stimuli may be infra-sensible (_atîndriya_ but not _anudbhûta_) [Footnote ref 1].