Quotes:Buddhi
H. P. Blavatsky
Buddhi. Universal Soul or Mind. Mahâbuddhi is a name of Mahat (see “Alaya”); also the spiritual Soul in man (the sixth principle), the vehicle of Atmâ exoterically the seventh.
Source: H. P. Blavatsky, The Theosophical Glossary, art. Buddhi