conditioned by external factors while the recognition is due to the intrinsic nature of the letters? And this very fact of recognition is that mental process which prevents us from looking on the apprehension of difference as having the letters for its object (so that the opponent was wrong in denying the existence of such a process). For how should, for instance, the one syllable ga, when it is pronounced in the same moment by several persons, be at the same time of different nature, viz. accented with the udatta, the anudatta, and the Svarita and nasal as well as non-nasal[201]? Or else[202]--and this is the preferable explanation--we assume that the difference of apprehension is caused not by the letters but by the tone (dhvani). By this tone we have to understand that which enters the ear of a person who is listening from a distance and not able to distinguish the separate letters, and which, for a person standing near, affects the letters with its own distinctions, such as high or low pitch and so on. It is on this tone that all the distinctions of udatta, anudatta, and so on depend, and not on the intrinsic nature of the letters; for they are recognised as the same whenever they are pronounced. On this theory only we gain a basis for the distinctive apprehension of the udatta, the anudatta, and the like. For on the theory first propounded (but now rejected), we should have to assume that the distinctions of udatta and so on are due to the processes of conjunction and disjunction described above, since the letters themselves, which are ever recognised as the same, are not different. But as those processes of conjunction and disjunction are not matter of perception, we cannot definitely ascertain in the letters any differences based on those processes, and hence the apprehension of the udatta and so on remains without a basis.--Nor should it be urged that from the difference of the udatta and so on there results also a difference of the letters recognised. For a difference in one matter does not involve a difference in some other matter which in itself is free from difference. Nobody, for instance, thinks that because the individuals are different from each other the species also contains a difference in itself.