The accuracy and tremendous success of science is primarily attributed to the accuracy and objectivity (i.e. repeatability) of observation of the reality that science explores.
The scientific method includes these steps:
Observation plays a role in the first and fourth steps in the above list, based upon the five physical senses and upon measurement techniques. It is understood that there are always certain limitations in making observations.
"Observe always that everything is the result of a change, and get used to thinking that there is nothing Nature loves so well as to change existing forms and to make new ones like them."
Meditations. iv. 36. - Marcus Aurelius
Observation in philosophical terms is the process of filtering sensory information through the thought process. Input is received via hearing, sight, smell, taste, or touch and then analyzed through either rational or irrational thought. You see a parent beat their child; you observe that such an action is either good or bad. Deductions about what behaviors are good or bad may be based on no way preferences about building relationships, or study of the consequences resulting from the observed behavior. With the passage of time, impressions stored in the consciousness about many related observations, together with the resulting relationships and consequences, permit the individual to build a construct about the moral implications of behavior.
The defining characteristic of observation is that it involves drawing conclusions, as well as building personal views about how to handle similar situations in the future, rather than simply registering that something has happened. But according to Jiddu Krishnamurti, observation does not imply drawing conclusions and building personal views. He stressed the non-accumulation of knowledge. Such an observation, he asserted, make the mind free.
People with "Observer" personalities are motivated by the desire to understand the facts about the world around them. Believing they are only worth what they contribute, Observers have learned to withdraw themselves, to watch with keen eyes, and to speak only when they think they can shake the world with their observations. Sometimes they do just that. However, some Observers are known to withdraw completely from the world, becoming reclusive hermits and fending off social contacts with abrasive cynicism. Observers generally fear incompetency and uselessness; they want to be capable and knowledgeable above all else.