Just because you see does not mean you observe. The difference between seeing and observing is fundamental to many aspects of life. Observation is more than simply seeing something, but rather a mental process involving both visual and thought.
In A Scandal in Bohemia, Sherlock Holmes teaches Watson the difference between seeing and observing:
“When I hear you give your reasons,” I remarked, “the thing always appears to me to be so ridiculously simple that I could easily do it myself, though at each successive instance of your reasoning, I am baffled until you explain your process. And yet I believe that my eyes are as good as yours.”
“Quite so,” he answered, lighting a cigarette, and throwing himself down into an armchair. “You see, but you do not observe. The distinction is clear. For example, you have frequently seen the steps which lead up from the hall to this room.”
“Well, some hundreds of times.”
“Then how many are there?”
“How many? I don’t know.”
“Quite so! You have not observed. And yet you have seen. That is just my point. Now, I know that there are seventeen steps, because I have both seen and observed.”
Often observation involves a conscious or unconscious linking to something that we already know, which brings us to an interesting point on how our experiences impact what we deem significant or not. Our experiences filter what we see.
When we are a novice at something, all observations are unexpected and worthy of our attention but as we learn more about a field we become more discerning about that which we consider important and noteworthy. The same holds true in life.
Observation is more than visual inputs (as found in The Art of Scientific Investigation):
It is important to realize that observation is much more than merely seeing something; it also involves a mental process. In all observations there are two elements : (a) the sense-perceptual element (usually visual) and (b) the mental, which, as we have seen, may be partly conscious and partly unconscious. Where the sense-perceptual element is relatively unimportant, it is often difficult to distinguish between an observation and an ordinary intuition. For example, this sort of thing is usually referred to as an observation: “I have noticed that I get hay fever whenever I go near horses.” The hay fever and the horses are perfectly obvious, it is the connection between the two that may require astuteness to notice at first, and this is a mental process not distinguishable from an intuition. Sometimes it is possible to draw a line between the noticing and the intuition, e.g. Aristotle commented that on observing that the bright side of the moon is always toward the sun, it may suddenly occur to the observer that the explanation is that the moon shines by the light of the sun.
On the two types of observation (as found in The Art of Scientific Investigation):
Claude Bernard distinguished two types of observation: (a) spontaneous or passive observations which are unexpected; and (b) induced or active observations which are deliberately sought, usually on account of an hypothesis. […] Effective spontaneous observation involves firstly noticing some object or event. The thing noticed will only become significant if the mind of the observer either consciously or unconsciously relates it to some relevant knowledge or past experience, or if in pondering on it subsequently he arrives at some hypothesis. In the last section attention was called to the fact that the mind is particularly sensitive to changes or differences. This is of use in scientific observation, but what is more important and more difficult is to observe (in this instance mainly a mental process) resemblances or correlations between things that on the surface appeared quite unrelated.
The role of the observer is to discriminate. Often the difference between the novice and the expert is their ability to quickly determine what’s relevant and what’s irrelevant (as found in The Art of Scientific Investigation):
One cannot observe everything closely, therefore one must discriminate and try to select the significant. When practicing a branch of science, the ‘trained’ observer deliberately looks for specific things which his training has taught him are significant, but in research he often has to rely on his own discrimination, guided only by his general scientific knowledge, judgment and perhaps an hypothesis which he entertains.
To develop the powers of observation you need to watch with an active mind (as found in The Art of Scientific Investigation):
Powers of observation can be developed by cultivating the habit of watching things with an active, enquiring mind. It is no exaggeration to say that well developed habits of observation are more important in research than large accumulations of academic learning.
Learning to observe (as found in The Art of Scientific Investigation):
Training in observation follows the same principles as training in any activity. At first one must do things consciously and laboriously, but with practice the activities gradually become automatic and unconscious and a habit is established. Effective scientific observation also requires a good background, for only by being familiar with the usual can we notice something as being unusual or unexplained.