"You have only one instrument, which is the mind; and the mind is the brain also. Therefore, to find out the truth of this matter, you must understand the ways of the mind, must you not? If the mind is crooked you will never see straight; if the mind is very limited you cannot perceive the illimitable. The mind is the instrument of perception and, to perceive truly, the mind must be made straight, it must be cleansed of all conditioning, of all fear. The mind must also be free of knowledge, because knowledge diverts the mind and makes things twisted. The enormous capacity of the mind to invent, to imagine, to speculate, to think, must not this capacity be put aside so that the mind is very clear and very simple? Because it is only the innocent mind, the mind that has experienced vastly and yet is free of knowledge and experience; it is only such a mind that can discover that which is more than brain and mind. Otherwise, what you discover will be colored by what you have already experienced, and your experience is the result of your conditioning."
-- Jiddu Krishnamurti

David Bohm proposed that thought is the source of our problems. The immediate implication from this statement, as Bohm pointed out, is that the way we solve our problems (by using thought) is the problem.

Jiddu Krishnamurti spent most of his life pointing out what thought has done to the world. Krishnamurti asserted that thought never has and never will solve humanity's problems and instead spoke of an awareness that is not thought.
Let's Be Clear
Thought is absolutely necessary. Thought goes on in everyone. We need thought to survive. Thought has brought about many, many good things. But thought has another side to it that's literally destroying and dividing us and we don't see this other side.
Thought Runs Deeper Than We Think
Quoted from Dialogue A Proposal by David Bohm, Donald Factor and Peter Garrett:
"We are using the word “thought” here to signify not only the products ofour conscious intellect but also our feelings, emotions, intentions and desires. It also includes such subtle, conditioned manifestations of learning as those that allow us to make sense of a succession of separate scenes within a cinema film or to translate the abstract symbols on road signs along with the tacit, non-verbal processes used in developing basic, mechanical skills such as riding a bicycle. In essence thought, in this sense of the word, is the active response of memory in every phase of life. Virtually all of our knowledge is produced, displayed, communicated, transformed and applied in thought.
To further clarify this approach, we propose that, with the aid of a little close attention, even that which we call rational thinking can be see to consist largely of responses conditioned and biased by previous thought. If we look carefully at what we generally take to be reality we begin to see that it includes a collection of concepts, memories and reflexes colored by our personal needs, fears, and desires, all of which are limited and distorted by the boundaries of language and the habits of our history, sex and culture. It is extremely difficult to disassemble this mixture or to ever be certain whether what we are perceiving – or what we may think about those perceptions – is at all accurate.
What makes this situation so serious is that thought generally conceals this problems from our immediate awareness and succeeds in generating a sense that the way each of us interprets the world is the only sensible way in which it can be interpreted. What is needed is a means by which we can slow down the process of thought in order to be able to observe it while it is actually occurring."
Most Of Thought's Activity Is Tacit

David Bohm quoted from 'On Dialogue':
"'Tacit' means that which is unspoken, which cannot be described -- like the knowledge required to ride a bicycle. It is the actual knowledge, and it may be coherent or not. I am proposing that thought is actually a subtle tacit process. The concrete process of thinking is very tacit. The meaning is basically tacit. And what we can say explicitly is only a very small part of it. I think we all realize that we do almost everything by this sort of tacit knowledge. Thought is emerging from the the tacit ground, and any fundamental change in thought will come from the tacit ground. So if we are communicating at the tacit level, then maybe thought is changing."
David Bohm quoted from 'Changing Consciousness':
"The point is, that memory is something you never see and in many ways has been interchanged with perception. The movement of the mind is far too subtle, complex and rapidly moving to be grasped by thought. So we are caught, responding from memory without knowing that this is actually happening. Our perceptions are shaped and colored by memory in ways that are not conscious. This evidently leads to irrelevant actions and ultimately to conflict."
Thought Is Doing All Kinds Of Things But It Is Telling Us That It Is Doing Nothing
On account of how subtle, tacit, and quick thought moves, and because the response of memory mixes in with perception in a way that we are not clear on, we really aren't seeing what thought is doing. This is a problem because thought is doing so much. Most often by the time we are aware of thought having done something it has already acted, so there is no question of trying to touch this whole process intellectually. Most of thought's actions we are incorrectly attributing to things that are not thought. Thought is incredibly active and paricipating in every experience we have yet our thoughts about thought are telling us that thought is just there passively waiting for us to use when we choose to do so.
Thought, Which Is The Response Of Memory, Prevents Intelligence
Jiddu Krishnamurti quoted from Ojai, California 4th Public Talk 19th June, 1934:
"Now memory is but the impediment to that intelligence; memory is independent of that intelligence; memory is the perpetuation of that "I" consciousness which is the result of environment, of that environment the full significance of which the mind has not seen. So memory stupefies, thwarts the ever becoming intelligence, the ever moving, timeless intelligence. Mind is intelligence, but memory has imposed itself on mind. That is, memory being that I consciousness, identifies itself with the mind, and the "I" consciousness comes as it were between intelligence and the mind, thus dividing, stupefying, thwarting, perverting it. So memory, identifying itself with mind, tries to become intelligence, which to me is wrong - if I may use the word"wrong" here - because mind itself is intelligence, and it is memory that perverts the mind and so clouds intelligence. And hence mind seems ever to seek that timeless intelligence, which is the mind itself.
So what is memory? Isn't memory incident, experience, fear, hope, longing, belief, idea, prejudice and tradition, action, deed, with their subtle and complex reactions? The moment there is hope, longing, fear, prejudice, temperament, it conditions the mind, and that conditioning creates memory, which obscures the clarity of mind which is intelligence. This memory rolls through time, coagulating and hardening itself into the self-consciousness of the "I". When you talk about the "I", it is that. It is the crystallizing, the hardening of the memory of your reactions, the reactions of experience, incidents, beliefs, ideals, and after becoming a solidified mass, that memory becomes identified and confused with the mind. If you think it over you will see this. Self-consciousness, or that consciousness of the particular, the "I", is nothing else but the bundle of memory, and time is nothing else but the field in which it can function and play. So this hardened mass of reactions cannot be resolved, cannot resolve itself backwards in time through analysis, the analysis of the past, because this very looking back, this analysis of the past is one of the tricks of memory itself. You know, taking an unhealthy pleasure in reasserting and reconditioning the past in the present is the constant activity, the metier of memory, isn't it? Please, this is not cleverness, this is not a philosophical concept. Just think it out for a minute, and you will see that this is true. There is this mass of reactions born out of condition, environment, prejudice, various longings and all these, therefore there is the thing which you call the "I"."
David Bohm quoted from 'Wholeness and the Implicate Order':
"What, then, is the relationship of intelligence to thought? Briefly, one can say that when thought functions on its own, it is mechanical and not intelligent, because it imposes its own generally irrelevant and unsuitable order drawn from memory. Thought is, however, capable of responding, not only from memory but also to the unconditioned perception of intelligence that can see, in each case, wehther or not a parituclar line of thought is relevant or fitting."
We Do Not Control Thought; Thought Controls Us
David Bohm described thought like a collective system of reflexes that moves on its own without a controller or thinker. Part of the difficulty is that these collective reflexes of thought have generated an image of the self or thinker and have attributed great powers to that image. This image enters our perception and is not examined deeply enough to be seen through. We have the image and feeling that we get to choose what we do with thought and knowledge and information but in actuality thought is reflexing out constantly and in a manner we do not have conscious control over. In different words, we are deeply conditioned and this conditioning reflexes out faster than we can reflectively mitigate it. Since this conditioning usually goes unexamined it is not experienced as the response of memory but instead it is experienced as part of reality.
The Point Is...
The proposal has been made that thought is source of our problems and that thought is doing all kinds of things we are not commonly seeing that is doing. Then, from this standpoint of thought not seeing its own activities, thought has, mostly unintentionally, created all of our unnecessary problems. Thought then tries to solve the very problems it itself created. These proposals about thought deserve serious attention, if for no other reason than that virtually everything we're doing in this world has thought at its foundation yet we barely have looked at this foundation. Isn't it amazing that amongst the numerous subjects we study and things we take interest in and observe we have grossly neglected attending to and observing the processes of thought on which all our studies and observations depend?
Links With More Information About The Basic Proposals:
An Introduction To The Teachings Of Jiddu Krishnamurti By David Bohm
A Short Introduction To David Bohm's Work On Thought