According to Osho, thoughts interfere because they preoccupy and crowd the mind, creating a fog—like dust on a mirror or tea overflowing a full cup—so reality cannot be reflected or received. Truth is the ultimate guest; it enters only when there is empty space. By relaxing, becoming silent, and dropping mental clutter, awareness opens to what is, beyond projections, desires, and private dream-worlds.
When your head is stuffed with thoughts, there’s no room for truth, so make quiet space inside first.
From the Discourses
Passages where Osho speaks to this question — each links to the complete discourse.
Why is it thought that thoughts interfere in knowing the truth?
And then there are a thousand and one functions. On each step of the journey there are problems -- because this journey is not like a plain highway. At each point there are diversions, at each point there are by-paths. It is a very zig-zag journey. It is almost a riddle. It is a labyrinth. Unless there is somebody who has gone the whole way and knows the way, there is a greater possibility that you will be lost somewhere, that you will take a wrong route. From each step the wrong route is available. And of a hundred routes, one is right, ninety-nine are wrong. This is the situation. You will need somebody to help you at each point of the journey. But as you grow, trust will also grow. When you take the first step with the Master you will see something has happened. Then more trust naturally…
The path of thought is a borrowed one; you proceed along a road paved with the ideas of others. Through argument and through different combinations of these secondhand thoughts you create the illusion of originality. Realization alone is original because realization is born within one's self. The known cannot lead to the unknown. Truth is unknown, and so familiar thoughts can never become stepping-stones to truth. Only by leaving thought behind can you pass through the doorway to truth. The perception of truth cannot happen in thought, it can happen only in the clear stream of thoughtless consciousness. Man collects experiences through his senses. All of these experiences belong to the outer world, because the senses only know that which is external. The senses have no access to one's inner being. It is these outer experiences that give rise to thought.
Osho: You cannot be open through effort. If you are thinking this, then you have not understood it. Thinking means non-understanding. The person who thinks is a man of non-understanding. A person who knows doesn't think. (much laughter) It is not a question of thinking. He sees, he is aware, but not in thinking. Thoughts are not opening, thoughts are closing; they close your mind. The more you are in a thinking mood, the more you are closed and isolated from the whole. If you are not thinking, if you just are, if you are in a state of being, then something comes. That is not thinking, that is the realization. That is not thinking, you have not thought it. And the more you have thought about it, the less is the possibility for its coming. The known must go for the unknown to come.
Therefore I say that the truth does not need imagination, but realization. The realization of the mind free from all imagination is the realization of the mind in a state of truth. We see the world when the mind is divided, when it is in a state of duality. We see the truth when the mind is an undivided entity, a unity. All concepts and all beliefs are conjecture and therefore not gateways to the truth. They are obstacles and lead nowhere. On the contrary, they block your path. The path of truth does not lie through them but beyond them. Please don't adopt any idea or concept, or form any conviction or belief about truth, because the belief you form will become an experience. And that experience is not real but mental, imaginary. These experiences are not spiritual.
When thought objects vanish, the thinking subject vanishes, as when the mind vanishes, objects vanish. Things are objects because of the subject; the mind is such because of things. Understand the relativity of these two and the basic reality: the unity of emptiness. In this emptiness the two are indistinguishable and each contains in itself the whole world. If you do not discriminate between coarse and fine you will not be tempted to prejudice and opinion.
Give love, and the begging bowl is there, your love has disappeared. Give your whole life, and the begging bowl is there, looking at you with complaining eyes. "You have not given anything. I am still empty." And the only proof that you have given is if the begging bowl is full -- and it is never full. Of course, the logic is clear: you have not given. You have achieved many many things -- they have all disappeared in the begging bowl. The mind is a self-destructive process. Before the mind disappears you will remain a beggar. Whatsoever you can gain will be in vain; you will remain empty. And if you dissolve this mind, through emptiness you become filled for the first time. You are no more, but you have become the whole. If you are, you will remain a beggar. If you are not, you become the…