I once sat in on a Sangha meeting where the learned monk was whipping up a lather: ‘Not-Two; Not-Three; Not-Four’, he pounded.
This is not what Not-Two means. It is not a swipe at all notions of plurality. Once you miss the significance of ‘Two’, you can go all the way to quadrillion. And it wouldn’t make any difference.
Not-Two: [Àdvaitham] is a term that predates Shūnyam. It has lots of layers and you won’t really notice them until you slip on one. But the three most relevant can be readily listed.
The first is the assumption of the ‘Independent and Separate ‘Self’. The ‘Two’ of the ‘Subject-Object Divide’. [‘Self and World’; ‘God and Man’, and so on.]
Not-Two is a categorical statement of Truth. It is not an appellation, not a name for an ‘Object’ [process, state, sentiment, anything you can objectify]. And the confounding of ‘Not-Two’ as a conventional reference, a name, is pervasive in the historical literature.
Not-Two actively locks in the Subject in a verbal hog-tie. You may not not say a word [or write a Post] about it.
Secondly, the open-ended ‘Not’. [See: ‘The ‘Not]
Thirdly, our reflexive tendency to abstract in Sign and Symbol [‘Doubles that Refer’] and hence make our World amenable to Logic and Language. In particular, expressions formulated as ‘Sign’, and further extended in Logic, Language and ‘Thought’. And then cheerfully contracted or expanded until we get seriously lost.
[There is nothing ‘wrong’ with sign or symbol, logic or language. The binary divides of Right and Wrong, Accuracy and Error are all assertions which themselves arise, take shape in these very vehicles. They are legitimate modeling constructs in context.]