User:Andries/Wikipedia:Definition of a fact


 * A fact is an actual state of affairs. To say of a sentence or proposition that it is  true is to say that it refers to a fact. As far as the encyclopedia is concerned, a fact is often a statement agreed to by the consensus of scholars or experts working on a topic. (New evidence might emerge so that the statement is no longer accepted as a fact; at that time the encyclopedia should be revised.) However a proposition that can be verified easily to be true even if sourced to only one reputable source can be classified as a fact too. In case a consensus about a certain subject by scholars contains, implicitly or explicitly, moral judgements then this consensus does not indicate a fact, but an opinion.

Assert facts, including facts about opinions — but don't assert opinions themselves. That a survey produced a certain published result is a fact. That there is a planet called Mars is a fact. That Plato was a philosopher is a fact. No one seriously disputes any of these things, so we can feel free to assert them.


 * An opinion is a view that someone holds, the content of which may or may not be verifiable. However, that a certain person or group expressed a certain opinion is a fact (that is, it is true that the person expressed the opinion) and it may be included in Wikipedia if it can be verified; that is, if you can cite a good source showing that the person or group expressed the opinion.