Now and again a daring soul, desiring immortality, has ...

Brian Hodgkinson, The Essence of Vedanta
Chapter 2: Knowledge and Ignorance
Two kinds of knowledge

'What is knowledge?' asks Arjuna in the Gita. Krishna replies that it is to know the field and the knower of the field (XIII, 1-2). What does this strange answer mean? The field refers to everything that can be perceived, in the widest sense of perception. In short, it is everything that is knowable. Thus all that may be experienced through the five senses and all that can be imagined, thought, felt or otherwise experienced inwardly is included in the field. But then if, as Krishna says, knowledge also means to know the knower of the field, then that would also be amongst the knowable, so that would be part of the field too. The solution of this dilemma is that the knower of the field is not knowable. How then can one know something which is not knowable? This question goes to the heart of the philosophy of Vedanta...

The distinction that Krishna makes, however, between the field and the knower of the field is quite different from all the distinctions ... It is not a distinction between outward empirical knowledge and inner introspective knowledge, nor between knowledge from experience and non-experiential, or a priori, knowledge, nor between empirical and logical, or analytic, knowledge. All these are within the field.

If we look more precisely at Krishna's answer, we find that the Sanskrit says something like 'to know the field and the knower of the field, that is real knowledge.' In other words, he suggests that there are two kinds of knowledge, a higher and lower. The latter is simply to know the field, the former is to know oneself as the knower of the field. This is confirmed elsewhere in the Gita and throughout Vedantic literature. As the modern Vedantist Nikhilananda wrote, 'Self-knowledge is vital. All other forms of knowledge are of secondary importance.' They cover more or less everything that we would call knowledge in the Western world.. Psychologists and similar investigators of the mind, or psyche, might object on the grounds that they study and discover knowledge of the self. But do they? Their field of investigation — the phrase is significant — is the contents of the mind, of the emotions and of the imagination, however deeply they penetrate these. How can the Vedantist be sure of this? The reason is that the self is not to be discovered by looking into the mind, but by finding that which is itself aware of the mind, the knower of the field.

The contrast between higher and lower knowledge is strikingly put in the Katha Upanishad:

'God made sense turn outward, man therefore looks outward, not into himself. Now and again a daring soul, desiring immortality, has looked back and found himself.'   (The Ten Principal Upanishads, pg. 33)

The passage does not simply refer to the five senses turning outwards to the spatial world. The 'sense' that turns outwards includes the sense of inner experience, thoughts and feelings and so on, for these are 'outside' the perceiving or knowing of self. The 'daring soul' is the man who wants real self-knowledge, who wants to know the knower of the field.

Brian Hodgkinson, The Essence of Vedanta,
Arcturus Publishing Ltd., Canada, pg. 17-19