443. hi, the causal particle.

The causal particle is hi (429). It may be compared with Greek γάρ, since like this it has a rather general employment when annexing sentences which contain some motive, reason, cause or even a mere illustration of that which precedes. For this reason, it may sometimes be rendered by „for” or „because” or „since,” sometimes with less emphasis, sometimes it is not to be translated at all. At the outset it was, indeed, a mere affirmative particle. Viddhaç. I, p. 7 śriyaḥ pradugdhe vipado ruṇaddhi yaśāṃsi sūte malinaṃ pramārṣṭi / saṃskāraśaucena paraṃ punīte śuddhā hi buddhiḥ kila kāmadhenuḥ (pure wisdom is indeed a cow of plenty; it milks blessings, it repels mishap, it produces glory, it cleanses the dirty, etc.) Kâd. I, p. 20 the king has declared his astonishment at the great gift of speech of the parrot which has been offered to him; in reply to this he is told kim atra citram / ete hi śukaśārikāprabhṛtayo vihaṅgaviśeṣā yathāśrutaṃ vācamuccārayanti (why wonder at this? since parrots, magpies and the like birds well repeat the words they have heard), Hit. 4 āhāranidrābhayamaithunaṃ ca sāmānyam etatpaśubhir narāṇām / dharmo hi teṣām udhiko viśeṣo dharmeṇa hīnāḥ paśubhiḥ samānāḥ.

For the rest, if it be necessary to signify the cause or motive as such, the relatives yataḥ and yasmāt are used. See 467.

443. 因果関係を表す不変化辞hi

因果関係を表す不変化辞はhiである（429）。これは古代ギリシャ語のγάρと比較でき、よってそれと同様に、何らかの動機（motive）、理由（reason）、原因（cause）、あるいは先行するものの単なる例示、を含む文章を接続する際には、かなり一般的に用いられる。このため、hiは「…のために」（for）、「なぜなら」（because）、「ゆえに」（since）で訳されたり、あまり強調されなかったり、完全には訳されなかったりすることがある。当初は、これは実際に、単に肯定を表す不変化辞であった。
Viddhaç. I, p. 7 śriyaḥ pradugdhe vipado ruṇaddhi yaśāṃsi sūte malinaṃ pramārṣṭi / saṃskāraśaucena paraṃ punīte śuddhā hi buddhiḥ kila kāmadhenuḥ (pure wisdom is indeed a cow of plenty; it milks blessings, it repels mishap, it produces glory, it cleanses the dirty, etc.)
Kâd. I, p. 20 the king has declared his astonishment at the great gift of speech of the parrot which has been offered to him; in reply to this he is told kim atra citram / ete hi śukaśārikāprabhṛtayo vihaṅgaviśeṣā yathāśrutaṃ vācamuccārayanti (why wonder at this? since parrots, magpies and the like birds well repeat the words they have heard)
Hit. 4 āhāranidrābhayamaithunaṃ ca sāmānyam etatpaśubhir narāṇām / dharmo hi teṣām udhiko viśeṣo dharmeṇa hīnāḥ paśubhiḥ samānāḥ

その他、hiのように原因や動機を表す必要がある場合には、関係詞yataḥとyasmātも用いられる。467をみよ。