According to the passage, human beings have which of the following in mind the most?

The phrase, what is it like, stands for a fundamental thought process. How does one go about observing and reporting on things and events that occupy the segments of earth space? Of all the infinite varieties of phenomena on the face of the earth, how does one decide what phenomena to observe? There is no such thing as a complete description of the earth or any part of it, as every microscopic point on the earth's surface differs from every other such point. Experience shows that the things observed are already familiar because they are like phenomena that occur at home or because they resemble the abstract images and models developed in the human mind. How are abstract images formed? Humans alone, among all other animals on the earth, possess language, and their words symbolize not only specific things but also mental images of classes of things. People can remember what they have seen or experienced because they attach a word symbol to them. During the long record of our efforts to gain more and more knowledge about the face of the earth as the human habitat, there has been a continuing interplay between things and events. The direct observation through the senses is described as a percept, and the mental image is described as a concept. Percepts are what some people describe as reality, in contrast to mental images, which are theoretical, implying that they are not real. The relation of percept to concept is not as simple as the definition implies. It is now quite clear that people of different cultures, or even individuals in the same culture, develop different mental images of reality, and what they perceive is a reflection of these preconceptions. The direct observation of things and events on the face of the earth is therefore clearly a function of the mental images of the mind of the observer, so much so that the whole idea of reality must be reconsidered. Concepts determine what the observer perceives, yet concepts are derived from the generalizations of previous percepts.