असिद्धम्

31 पूर्वत्रासिद्धम् 8.2.1

हर इह, हरयिह

असिद्धम् implies a form of rule ordering so that only desired outputs are achieved and undesirable outputs are averted.

This implies we order rules such that B is invisible to A. Thus A will be sequentially placed before B in the अष्टाध्यायी

This ordering has two important implications:

1. आदेशलक्षणप्रतिशेध

Output of B is invisible to A, so B can not feed A.

Here consider

लोपः शाकल्यस्य 8.3.19 B

आद् गुणः 6.1.87 A

Consider the case where we have हरे इह

By एचोऽयवायावः 6.1.78, this should yield हर + अय् + इह

Now by applying लोपः शाकल्यस्य 8.3.19 B, we can optionally delete the अय् and get हर इह

Now the important question is whether this now becomes हरेह by virtue of आद् गुणः 6.1.87 A

The answer is NO because B can not feed A as B is invisible to A

2. उत्सर्गलक्षणभाव

Input of B is visible to A, so B can not bleed A

This is the case where both rules are immediately applicable

भुग्न

Here there are two rules at stake:

ओदितश्च 8.2.45 B

ओदितश्च धातोः निष्ठातकारस्य नत्वम् इत्यर्थः

त in niShTha suffixes (such as the past participle ending -क्त) is replaced by न after roots with the marker ओ.

चोः कुः 8.2.30 A

चवर्गस्य कवर्गः स्यात् झलि पदान्ते च

A palatal (चवर्ग) is replaced by a velar (कवर्ग) before a झल् and at the end of a word. E.g., वच् + तुमुन् -> वक्तुम्

In the underlying example, भुज्ओ-क्त, both rules are applicable: the replacement of त by न, and the substitution of the root-final - ज् by - ग् before a झल्. If त -> न were to take place first, it would bleed ज् -> ग्, yielding the wrong term

*भुज्न (->भुज्ज्ञ by स्तोः श्चुना श्चुः 8.4.41).

Does this happen in reality?

The answer is NO because B can not bleed A as B takes into effect after A

In other words, in order to ensure that B does not count with respect to A, it is placed after it in the त्रिपादी. It is thereby असिद्ध with respect to A and therefore fails to bleed it.

So the correct sequence of application would be

भुज्ओ-क्त by 8.2.30 would yield भुग्ओ-क्त. Now applying 8.2.45 would yield the correct derivation भुग्न.

Summary:

The learner is urged to remember that असिद्धत्वं in the अष्टाध्यायी is simply a restriction on rule ordering such that correct derivations are produced.