I have been telling you of ‘the mind’ so far.
But the Acharya has referred to ‘buddhi’, the intellect. *samyak AsthApanaM buddheH* are his words – namely, ‘the intellect must be caught hold of and fixed in Brahman’. The intellect (*buddhi*) is only one particular aspect of the mind.
Cit is Knowledge. The organ that the JIva has that is associated with knowledge is ‘cittaM’. This is an internal organ; called ‘antah-karaNaM’.
By ‘Knowledge’ is not meant just what is done by the intellect (buddhi). Though what is done by the intellect is part of this Knowledge, ‘cittaM’ is not just that. The feelings that arise in the mind (manas) is also part of it.
The work of the mind, the work of the intellect, what the mind thinks, feels, what the intellect knows – all these together constitute what is called ‘cittaM’. Because of this combination of works of both the mind and intellect, it is customary in advaita works to refer to the process of cleaning up the mind and the intellect and of focussing them as ‘citta-shuddhi, citta aikAgriyaM’.
There are four: cittaM, manas, buddhi, ahamkAraM. The four together constitute ‘antah-karaNaM’. ‘Thought’ is something that is common to all the four. But its source is ‘cittaM’. The ‘cittam’ that produces thought associates itself with the other three.
Manas is the instrument of feeling. It does not know good and bad. It drowns itself in all kinds of feelings. It is the intellect that is the instrument of discrimination between good and bad. Only the intellect has the power of judgment.