The vanishing of duality means there is only One. And the One is Atman, no doubt.
In summary the Acharya’s clarion call is : “One should not worry about either what is directly an unhappy thing or about what appears to be pleasant but in reality is also a miserable thing.
‘Not worrying’ means ‘not wailing’ about it. Nor should one look for anitdotes for either the sukha (happiness) or the dukha (unhappiness). Silently one should be forbearing both”.
*sahanaM sarva-dukhAnAM apratIkAra-pUrvakaM /
cintA-vilApa-rahitaM sA titikshhaa nigadyate //* (Viveka Chudamani #24 (or 25))
sA titikshhaa nigadyate : She is said to be ‘titikshhaa’
sarva-dukhAnAM sahanaM : forbearing all unhappiness Note that so-called happiness is also included in the ‘unhappiness’.
cintA-vilApa-rahitaM : without worry (*cintA*) or lament (*vilApa*).
When he talks about ‘nitya-anitya-vastu-viveka’ (Discrimination between the eternal and the ephemeral) he says *so’yaM nityAnitya- vastu-vivekaH*; here he uses *saH ayaM* -- ‘that is he’ – thereby invoking a masculine construction. The word ‘vivekaH’ is masculine.
Maybe because of the age-old traditional opinion that a feminine mind is prone to vacillation and a masculine mind has a discriminating tendency. On the other hand the concept of dispassion is indicated by the neuter gender specification *tad-vairAgyaM* -- That is dispassion.
So in discrimination there is an action (though mental) whereas in dispassion there is not so much action.