“If one is to observe, M. Endymion, one must be in the proper place to observe.”

Source: De architectura (The Ten Books On Architecture) (~ 15BC), Book I, Chapter II, Sec. 9

Budo Secrets (2002)
Context: Jigoro Kano's Five Principles of Judo:
1. Carefully observe oneself and one's situation, carefully observe others, and carefully observe one's environment,
2. Seize the initiative in whatever you undertake,
3. Consider fully, act decisively,
4. Know when to stop,
5. Keep to the middle.

5th Public Talk Saanen (26th July 1970); also in "Fear and Pleasure", The Collected Works, Vol. X
1970s
Context: Do you decide to observe? Or do you merely observe? Do you decide and say, "I am going to observe and learn"? For then there is the question: "Who is deciding?" Is it will that says, "I must"? And when it fails, it chastises itself further and says, "I must, must, must"; in that there is conflict; therefore the state of mind that has decided to observe is not observation at all. You are walking down the road, somebody passes you by, you observe and you may say to yourself, "How ugly he is; how he smells; I wish he would not do this or that". You are aware of your responses to that passer-by, you are aware that you are judging, condemning or justifying; you are observing. You do not say, "I must not judge, I must not justify". In being aware of your responses, there is no decision at all. You see somebody who insulted you yesterday. Immediately all your hackles are up, you become nervous or anxious, you begin to dislike; be aware of your dislike, be aware of all that, do not "decide" to be aware. Observe, and in that observation there is neither the "observer" nor the "observed" — there is only observation taking place. The "observer" exists only when you accumulate in the observation; when you say, "He is my friend because he has flattered me", or, "He is not my friend, because he has said something ugly about me, or something true which I do not like." That is accumulation through observation and that accumulation is the observer. When you observe without accumulation, then there is no judgement.

Source: Red Dragon

Saanen, Switzerland (5 August 1973)
1970s
Context: Now, one sees all that by observing, by being aware, watching, one is aware of all this. Then out of that awareness you see there is no division between the observer and the observed. It is a trick of thought which demands security. Please don't madam, please. And by being aware it sees the observer is the observed, that violence is the observer, violence is not different from the observer. Now how is the observer to end himself and not be violent? Have you understood my question so far? I think so. Right? The observer is the observed, there is no division and therefore no conflict. And is the observer then, knowing all the intricacies of naming, linguistically caught in the image of violence, what happens to that violence? If the observer is violent, can the observer end, otherwise violence will go on? Can the observer end himself, because he is violent? Or what reality has the observer? Right sir? Is he merely put together by words, by experience, by knowledge? So is he put together by the past? So is he the past? Right? Which means the mind is living in the past. Right? obviously. You are living in the past. Right? No? As long as there is an observer there must be living in the past, obviously. And all our life is based on the past, memories, knowledge, images, according to which you react, which is your conditioning, is the past. And living has become the living of the past in the present, modified in the future. That's all, as long as the observer is living. Now does the mind see this as a truth, as a reality, that all my life is living in the past? I may paint most abstract pictures, write the most modern poems, invent the most extraordinary machinery, but I am still living in the past.

observes it
Source: 1980s, Notes on an epistemology for living things, 1981, p.258

Source: Les Miserables

IV, 32
Meditations (c. 121–180 AD), Book IV