Objective can be contrasted to “subjective”. Animals have evolved complex nervous systems that function to convert sensory experiences into useful memories. Our memories provide us with an understanding of the world that is less than perfect. Personal experiences can be categorized as “subjective” and subject to many sources of error. A goal of science is to discover methods to test the validity of subjective experiences and our conceptual networks that arise from subjective experiences. One method is to carefully describe the conditions of specific subjective experiences so that other people can repeat them. Within science, it is often desirable to make use of mechanical devices for making observations. Once observations are mechanically recorded, any number of witnesses can verify the recorded results. To the extent that many different people can test an observation in many different ways, we remove ourselves from the danger of errors inherent in subjective experience and describe our understanding of what is observed as increasingly objective. Objectivity implies that what is known is independent of one's perceptions of them, or one's personal feelings, opinions and beliefs. It is thus opposed to subjectivity.