18.31

यया धर्ममधर्मं च
कार्यं चाकार्यमेव च ।
अयथावत्प्रजानाति
बुद्धिः सा पार्थ राजसी ॥

yayā dharmam adharmaṃ ca kāryaṃ cākāryam eva ca
ayathāvat prajānāti buddhiḥ sā pārtha rājasī

Kṛṣṇa (कृष्ण) is still speaking, to Arjuna (अर्जुन). This is the intellect of rajas (रजस्).

The verse

The intellect by which one discerns dharma (धर्म) and what is not dharma (धर्म), and what is to be done and what is not, but not as they are: that, son of Pṛthā (पृथा), is rājasī (राजसी).

नेपालीमा

जुन बुद्धिले धर्म र धर्म नभएको कुरा, र गर्नुपर्ने र नगर्नुपर्ने चिन्छ, तर जस्ता हुन् त्यस्तै चिन्दैन, हे पृथाका छोरा, त्यो राजसी हो।

Where it sits

18.30 knew the pairs as they are, and this intellect has right and wrong, what to do and what not to do, and misses their real shape: ayathāvat (अयथावत्) is the whole difference. 18.32 reverses them.

Split: यया + धर्मम् + अधर्मम् + च + कार्यम् + च + अकार्यम् + एव + च + अयथावत् + प्रजानाति + बुद्धिः + सा + पार्थ + राजसी

yayā + dharmam + adharmam + ca + kāryam + ca + akāryam + eva + ca + ayathāvat + prajānāti + buddhiḥ + sā + pārtha + rājasī

Sanskrit, in depth

The words

देवनागरीWordGrammarSense
ययाyayāinstrumental singular feminineby which.
धर्मम्dharmamaccusative singulardharma (धर्म). What is right.
अधर्मम्adharmamaccusative singularwhat is not dharma (धर्म).
चcaindeclinableand.
कार्यम्kāryamaccusative singularwhat is to be done.
चcaindeclinableand.
अकार्यम्akāryamaccusative singularwhat is not to be done.
एवevaindeclinableindeed.
चcaindeclinableand.
अयथावत्ayathāvatindeclinablenot as it is. Not duly.
प्रजानातिprajānātipresent, 3rd singular of pra-jñā (प्र-ज्ञा)discerns. Knows.
बुद्धिःbuddhiḥnominative singularintellect.
साsānominative singular femininethat.
पार्थpārthavocativeson of Pṛthā (पृथा).
राजसीrājasīnominative singular femininerājasī (राजसी). Agrees with buddhiḥ (बुद्धिः).

The phrases

यया धर्मम् अधर्मम् च yayā dharmam adharmam ca is the first pair this intellect takes up: right, and what is not right. धर्मम् अधर्मम् dharmam adharmam is dharmam adharmam (धर्ममधर्मम्). कार्यम् च अकार्यम् एव च kāryaṃ ca akāryam eva ca is the second pair: what to do, and what not to do. ca akāryam (च अकार्यम्) is cākāryam (चाकार्यम्).

ayathāvat prajānāti (अयथावत् प्रजानाति) is the flaw. It discerns them, and not as they are. ayathāvat prajānāti (अयथावत् प्रजानाति) is written ayathāvat prajānāti (अयथावत्प्रजानाति). buddhiḥ sā pārtha rājasī (बुद्धिः सा पार्थ राजसी) names it.

Sanskrit in this line

yayā (यया) is instrumental feminine, "by which," and it agrees with buddhiḥ (बुद्धिः). The intellect is the means of the discerning. prajānāti (प्रजानाति) is the verb. ayathāvat (अयथावत्) is an indeclinable, not an adjective. It does not take a case. It says the manner: not as the thing truly is. The positive yathāvat (यथावत्) was "duly" in 18.19. The a- (अ-) reverses the manner and leaves the form indeclinable.

Say it back

Cover the English. Say what it discerns, and that it discerns it wrongly. If ayathāvat (अयथावत्) drops out, this intellect has become the one in 18.30.