Atman originally meant air as the Greek atmos, Gothic ahma, Zend tmánam, Sanscrit त्मानं and आत्मानं, Cuniform adam, Persian dam, whence we derive Sans. अहं Hindi हम् Uria and Prakrit अमू and Bengali आमि, मुइ &c. The Greek and Latin ego and German ich are all derived from the same source. The Romance je and Hindi ji are corruptions of Sanskrit जीब meaning life and spirit. Again the Páli अत्ता and the Prakrit आप्पा is from the Sanscrit आत्मा, which is आप् in Hindi, आपन in Bengali and अप्पन in Uria &c. The Persian “man” is evidently the Sátman by elision of the initial syllable.
These meanings of átman = the self and ego form the basis of the knowledge of the Divine soul both of the Hindu as of any other people, who from the consciousness of their own selves rise to that of the Supreme. Thus says Max Müller on the subject, “A Hindu speaking of himself आत्मन् spoke also, though unconsciously of the soul of the universe परमात्मन्, and to know himself, was to him to know both his own self and the Universal soul, or to know himself in the Divine self.”
We give below the different lights in which the Divine soul was viewed by the different schools of Hindu philosophy, and adopted accordingly in their respective modes of Yoga meditation. The Upanishads called it Brahma of eternal and infinite wisdom नित्यं ज्ञानमनन्तं ब्रह्म ।
The Vedantists;—A Being full of intelligence and blissfulness सच्चिदानन्द स्वरूपं ।
The Sánkaras;—A continued consciousness of one self. सनित्योपलब्धि स्वरूपोऽहमात्मा । The doctrine of Descartes and Malebranche.
The Materialists—convert the soul to all material forms देहमात्रमिति प्रकृत्यः ।
The Lokáyatas—take the body with intelligence to be the soul; चैतन्यबिशिष्टः देहमात्मां ।
The Chárvákas—call the organs and sensations as soul; इन्द्रियान्येबात्मेति ।
Do. Another sect—take the cognitive faculties as such; चेतनान्यात्मेत्यपरे चार्ब्बाकाः ।
Do. Others—Understand the mind as soul मनो एबात्मेत्यन्ये ।