473. d) yathā, when a causal particle.

d.) Finally, yathā may sometimes have the nature of a causal particle. This seems to have been more usual in ancient literature, than afterwards. Ch. Up. 6, 13, 1 uddhāvamṛśya na viveda yathā vilīnamevāṅga (he [the son] having looked for it [the salt, he had placed in the water] did not find it, for, of course, it was melted), R. 3, 57, 19 Râma surmises, Sîtâ will have incurred some harm. sarvathā janakātmajā / vinaṣṭā bhakṣitā vāpi rākṣasair anacāribhiḥ / aśubhānyeva bhūyiṣṭhaṃ yathā prādurbhavanti me (— as it is chiefly prognostics of evil, that appear to me).

This causal meaning of yathā is sometimes indicated by adding hi the exponent of causality. R. 3, 11, 47 etad evāśramapadaṃ nūnaṃ tasya… agastyasya muner bhrāturdṛśyate… yathā hīme vanasyāsya jñātāḥ pathi sahasraśaḥ… drumāḥ.

In the instances quoted the clause with yathā follows the main sentence. If it precedes, we may translate it by as much as, considering, etc. Nala. 21, 8 yathāsau rathanirghoṣaḥ pūrayann iva medinīm / mamāhlādayate ceto nala eṣa mahīpatiḥ (considering the joy, which causes to me the sound of the chariot, I know it is Nala).

473. d) 原因を表すyathā

d.) 最後に、yathāは原因を表す不変化辞の性格をもつことがある。これは後代の文学作品よりも古い作品のほうでより一般的であったようである。
Ch. Up. 6, 13, 1 uddhāvamṛśya na viveda yathā vilīnamevāṅga (he [the son] having looked for it [the salt, he had placed in the water] did not find it, for, of course, it was melted)
R. 3, 57, 19 Râma surmises, Sîtâ will have incurred some harm. sarvathā janakātmajā / vinaṣṭā bhakṣitā vāpi rākṣasair anacāribhiḥ / aśubhānyeva bhūyiṣṭhaṃ yathā prādurbhavanti me (— as it is chiefly prognostics of evil, that appear to me)

yathāのこの原因を表す意味は、原因性の指示詞hiを付加することによって表示されることがある。
R. 3, 11, 47 etad evāśramapadaṃ nūnaṃ tasya… agastyasya muner bhrāturdṛśyate… yathā hīme vanasyāsya jñātāḥ pathi sahasraśaḥ… drumāḥ

引用した例では、yathāを伴う節が主文の後に続く。先行する場合には、yathāを「…と同じ程度に…」や「…の割には」などで翻訳しうる。
Nala. 21, 8 yathāsau rathanirghoṣaḥ pūrayann iva medinīm / mamāhlādayate ceto nala eṣa mahīpatiḥ (considering the joy, which causes to me the sound of the chariot, I know it is Nala)