Existentialism asserts that people actually make decisions based on subjective meaning rather than pure rationality. A symptom can be subjective or objective. Social reality exists at both the subjective and objective levels. Feeling types make judgments based on subjective and personal values. Statistical control is based on analyses of objective and subjective data. Psychogeography combines subjective and objective knowledge and studies. Such is the difference between subjective and objective points of view. There are various types of objective and subjective questions. The use of empirical evidence negates this effect of personal (i.e., subjective) experience or time. The test is both subjective and objective. This would separate everything as objective and subjective. Researchers have sought to understand the relationship between objective and subjective ambivalence. Nagel uses the metaphor of bats to clarify the distinction between subjective and objective concepts. Policies can assist in both subjective and objective decision making. Here, the test is both subjective and objective.