स्थानेऽन्तरतमः

This sutra also lays down another rule of paribhasha. To explain this we must take an example. The guna of इ, उ, ऋ, and लृ, is अ, ए, ओ. There is nothing to specify what letter is the guna of what. It might be said that ओ is the guna of इ because the definitions as laid down up to so far, do not say anywhere that ओ is not the guna of इ. So that when in a word like चि we are told 'let there be the guna of इ' we do not know what specific guna letter is to be substituted, whether it is अ, ए or ओ. To clear up this doubt, this sutra declares that the likest of its significates is to be substituted. Now the nearest in place to इ is ए, both having their place of pronunciation, the palate. Similarly ओ is the guna of उ, because both are labials.

There are four sorts of proximity or nearness :-(1) nearness in place or स्थान (i.e. palate, throat &c.); (2) nearness in meaning or अर्थ (such as, singular terminations to be used after words used in the sense of singular); (3) nearness in quantity or प्रमाण (such as a short vowel to replace a short vowel, a long vowel, a long one); (4) nearness in quality or गुण (such as aspirates to replace aspirates, and sonants to replace sonants). Of all these approximates the first vis., the nearness in the organ of utterance has preference, in the selection of proper substitute.

(1). Thus in applying rule 6.1.101, \when a homogeneous vowel follows ak, the corresponding long vowel is the substitute for both,\ we must have recourse to the present sutra for finding the proper vowel. Thus - दण्ड + अग्रं = दण्डग्रं; here the substitution of the long आ, for the two short अ's, is an example of substitution by nearness of place, for both अ and आ are gutturals.

(2). A good example of substitution by the sense of the word is afforded by 6.1.63:- \The words पद्, दत्, नस् &c., are the substitutes when the case-affixes शस् (acc.-pl.) &c., follow.\ Here, we know the substitutes, but we do not know of what they are the substitutes. We apply the maxim of अर्थतः \that only can become a substitute which has the power to express the meaning of the original, i. e., a substitute takes the place of that the meaning of which it is able to express.\ Thus we find that पद् is the substitute of पाद, दत् of दन्त, नस् of नासिका, &c., which convey the same meaning and contain almost the same letters. Another example of this is afforded by 6.3.34, by which feminine words in a compound are changed into masculine. Thus वातण्डी (fem) + युवती = वातण्ड्ययुवतिः.

(3). An example of prosodial substitution (प्रमाणतः) is afforded by rule 8.2.80, \उ is the substitute of what comes after the द् of अदस् not ending in स् and in the room of द् there is म्.\ Thus अम + स्मै = अम् + अस्मै = अमुष्मै; अम + भ्याम् = अमा + भ्याम् 7.3.102 = अम् + ऊभ्याम् = अमूभ्याम्. Here, short उ replaces the short अ, and the long ऊ replaces the long आ.

(4). An illustration of qualitative substitution is afforded by 7.3.52, \a letter of the guttural class is substituted for च् and ज् when an affix having an indicatory घ् follows.\ Applying the rule of गुणतः we find that क् which is an alpaprana and aghosha letter replaces च् having the same quality; while ज् which is ghosha, and alpaprana is replaced by the letter ग् possessing similar quality. Thus पच् + घञ् 3.3.18 = पाकः; त्यज् + घञ् = त्यागः; रञ्ज् + घञ् = रागः ॥

Though the anuvritti of the word sthana was understood in this sutra from the last, the repetition of this word indicates the existence of the following paribhasha :-

Wherever there exist several kinds of proximity between that for which something else shall be substituted, and its possible substitutes, there the proximity as to the organ of speech is weightier than the rest, i. e., there that only is substituted which is nearest as regards the organs of speech with which both are uttered.

Thus in finding the guna substitutes of इ and उ out of the three guna letters अ, ए and ओ, we find that अ is a proximate substitute having regard to prosodial measure, i. e., अ and इ and उ have all one matra; while having regard to the proximity of the organ of utterance, we get ए and ओ; the latter however prevails to the exclusion of the first; as चेता, स्तोता.

Why do we use the word \likest\ in the superlative degree? Where there are many sort of proximities, the likest must be taken. Thus वाक् + हसति = वाग्घसति. Here, by 8.4.62, \after a letter of झय् class, ह् is changed into a letter homogeneous with the preceding,\ ह् must be changed into a letter of the class क्. Out of the five letters of this class, ख् and ह् are both aspirates, but ख् is hard, and ह् is soft; so ग् an ह् are both soft, but ग् is unaspirate, and is ह् aspirate, therefore these must be rejected; the only letter which has the nearest approach to ह्, is घ्, which is both soft and aspirate. Similarly in त्रिष्टुब्भसति, the ह has been changed into भ.,