“Vikalpa is a particular kind of Citta Vṛtti in which understanding
arises from the spoken word. Is this kind of understanding valid or not?
Patañjali, in the definitive Mahābhāṣya commentary on Saṃskṛta grammar,
states that the essence of the spoken word is not separate from the fact
or object it refers to. Objects themselves cannot express their various aspects;
only Śabda can present them to us. Śabda can convey nuances
of meaning that only a special faculty of the mind can grasp.
Such an ability to comprehend is not given to everyone.
The essence of this Sūtra is that Vikalpa is the mental activity by
which what is spoken is understood to mean what it represents,
even when the actual thing is not present.
Thus when we hear the word Sarpa we know it means snake
even though there is no snake present at the moment.”
– T Krishnamacharya on Yoga Sūtra Chapter One verse 9

“Imagination is knowledge
that comes from words
empty of substance.”
– Paul Harvey on Yoga Sūtra Chapter One verse 9

“What you are looking at is coloured
by where you are looking from.
Where you are looking from is coloured
by what you are looking at.
So the mind may know or not know, 
where it is actually looking from,
or what it is actually looking at.
Or even not know that it doesn’t know
the nuances inherent in what and where.”
– Paul Harvey on Yoga Sūtra Chapter Four verse 17