Opinion

In general, an opinion is a judgment, viewpoint, or statement that is not conclusive. It may deal with subjective matters in which there is no conclusive finding. What distinguishes fact from opinion is that facts are more likely to be verifiable, i.e. can be agreed to by the consensus of experts. An example is: "United States of America was involved in the Vietnam War" versus "United States of America was right to get involved in the Vietnam War". An opinion may be supported by facts and principles, in which case it becomes an argument. Different people may draw opposing conclusions (opinions) even if they agree on the same set of facts. Opinions rarely change without new arguments being presented. It can be reasoned that one opinion is better supported by the facts than another by analyzing the supporting arguments. In casual use, the term opinion may be the result of a person's perspective, understanding, particular feelings, beliefs, and desires. It may refer to unsubstantiated information, in contrast to knowledge and fact.

Collective or professional opinions are defined as meeting a higher standard to substantiate the opinion. (see below)

In economics, other social sciences and philosophy, analysis of social phenomena based on one's own opinion(s) is referred to as normative analysis (what ought to be), as opposed to positive analysis, which is based on scientific observation (what materially is or is empirically demonstrable).

Historically, the distinction of demonstrated knowledge and opinion was articulated by Ancient Greek philosophers. Today, Plato's analogy of the divided line is a well-known illustration of the distinction between knowledge and opinion, or knowledge and belief, in customary terminology of contemporary philosophy. Opinions can be persuasive, but only the assertions they are based on can be said to be true or false.

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