The three OVM Viewpoints are defined thinking tools used to understand belief, evidence, and doubt: true believer, empiricist, and true skeptic.
In ordinary usage, the term viewpoint often overlaps with perspective or even lens, but not in TST. In TST, a viewpoint is a thinking position available for any mind to consider, a perspective is the position of a mind on a specific topic, and a lens is an available worldview approach to things like truth, belief, and ethics.
OVM Viewpoints is a specific TST term.
The Open Viewpoint Method uses three viewpoints to explore steelman arguments of a topic. The True Believer viewpoint represents the strongest available argument in favor of a topic. The Empiricist viewpoint represents the evidence-based inquiry where science and reason are put above all else. The True Skeptic viewpoint represents the strongest available argument against a topic. These are not labels for entire people. They are tools for exploring how an idea looks from different positions. Take evolution. If you believe evolution, before engaging with a creationist, or better yet, to evaluate the strongest points against evolution, you steelman either an argument against evolution or an argument for creationism; or both. And vice versa, if you are a creationist who has not looked honestly at evolution, create the best steelman argument you can for evolution, open your mind, and evaluate each point.
By examining at least the opposing view of your own, you can better understand disagreements, avoid rigid thinking, and evaluate ideas without confusing a person’s beliefs with the whole person.