[2] The opinions of those with significant experience, highly trained or possessing an advanced degree are often considered a form of proof.
The main limitation lies not in the standard, but in the human inability to acquire all facts of an experience.
According to consensus gentium, the universal consent of all mankind (all humans holding a distinct belief), proves it is true.
It is inadequate as a criterion because it treats facts in an isolated fashion without true cohesion and integration; nevertheless it remains a necessary condition for the truth of any argument, owing to the law of noncontradiction.
For example, the premises are a priori (or self-apparent), requiring another test of truth to employ this criterion.
An additional test beyond this "definition" is required to determine the precise degree of similarity between what is posited and what exists in objective reality.
Most people consciously or unknowingly employ custom as a criterion of truth, based on the assumption that doing what is customary will prevent error.
For example, a seasoned businessman will put aside his emotions and search for the best available facts when making an investment.
Scholars have sometimes come upon valid theories and proofs while daydreaming or otherwise mentally occupied with something bearing no apparent relationship to the truth they seek to reveal.
Intuitive knowledge requires testing by means of other criteria of truth in order to confirm its accuracy.
In democratic systems, majority rule is used to determine group decisions, particularly those relating to personal morality and social behavior.
While majority rule may make for a good democratic system, it is a poor determinant of truth, subject to the criticisms of the broad version of consensus gentium.
Similarly, there are a number of sense experiments which show a disconnect between the perceived sensation and the reality of its cause.
Although pragmatism is considered a valuable criterion, it must be used with caution and reservation, due to its potential for false positives.
For example, a doctor may prescribe a patient medication for an illness, but it could later turn out that a placebo is equally effective.
However, it has validity as a test, particularly in the form William Ernest Hocking called "negative pragmatism".
It may be a valid reference of truth for an individual, but it is inadequate for providing a coherent proof of the knowledge to others.
For example, most people will not convert to another faith simply because the other religion is centuries (or even millennia) older than their current beliefs.
[15] Tradition, closely related to custom, is the standard stating that which is held for generations is true.
Those accepting tradition argue that ideas gaining the loyalty multiple generations possesses a measure of credibility.