What is Jñāna in the Bhagavad Gita?
Jñāna is knowledge, but the Gita is careful about which kind. It is not information. 18.20 defines the clearest sort as the knowledge by which you see one undivided reality in everything that lives, undivided among the divided. That is a way of seeing, not a quantity of facts.
The distinction matters because the middle grade looks so respectable. 18.21 describes knowledge that sees only separate things, each apart. Nothing in it is factually wrong. It can tell you everything about how people differ and nothing about what connects them, and it is the knowledge of somebody who has done the reading.
18.10 calls the final state one whose doubts are cut rather than answered, which is the most useful phrase in this area. Some questions do not end when information arrives, because they were never short of information. They end when whatever held them taut is let go. And 4.38 makes the practical claim that this knowledge is not imported: in time a person finds it within himself.
The verses 16
4.33
Better than any offering made of things is the offering of knowing, Arjuna.
4.34
Learn it by going and bowing, by asking properly, by being of use.
4.37
As a fire well lit turns firewood to ash, Arjuna, the fire of knowing turns every action to ash in the same way.
4.38
There is nothing in this world as clean as knowing.
4.39
The one who trusts it gets it - devoted to it, with the senses in hand.
5.15
The all-pervading takes on no one's wrongdoing, and no one's good deed either.
5.16
But for those whose not-knowing has been destroyed by knowing the self, their knowing lights up that highest thing, the way the sun does.
7.2
I shall tell you this knowledge in full, together with the living realisation of it.
13.2
Krishna said: This body is called the field, Arjuna.
13.11
… unbroken devotion to me, joined to nothing else; a liking for quiet places; no taste for crowds of people…
13.12
… constancy in the knowledge of the self, and keeping in view what the knowledge of truth is for.
13.18
It is the light of lights, said to be beyond darkness.
14.1
Krishna said: I will tell you again the highest knowledge, the best of all knowing - knowing which, all the sages went from here to the highest completion.
18.20
The knowledge by which you see one unchanging being in everything that lives, undivided among the divided: know that knowledge as clear.
18.21
But the knowledge that sees only separate things of many kinds, each one apart, in all that lives: know that knowledge as driven.
18.22
And the knowledge that clings to one single thing as though it were the whole, with no reason behind it, missing what is actually the case, and narrow: that is called dark.