Skepticism (Greek skeptiko => an inquirer) is a philosophical attitude that first appeared in ancient Greece around the 5th century BCE. There are two basic methods to prove an assertion’s truth or falsity: rationality and non-rationality. In the first case, rationality, logical reasoning, or empiricism (empirical evidence.) In the second case, non-rationality, intuition, instinct, feeling, propaganda, or authority.
Of course, now we are left with the problem of determining an opinion’s certainty. Bertrand Russell claimed that it is possible to decide on the degree of certainty of an opinion by consulting experts. He suggests three potential outcomes.
- When the experts agree, the opposite opinion cannot be held to be certain.
- When the experts do not agree, no opinion can be regarded as certain.
- When the experts all hold that no sufficient grounds for a positive opinion exist, the skeptic would do well to suspend judgment. (BRSE p2)
Thus, the certainty of the truth or falsity of an opinion can be ascertained by the proportion of expert opinions.
The rational skeptic must ensure that the experts arrive at their opinions through logical reasoning or empirical evidence. In short, through scientific research. Furthermore, the skeptic’s selection of experts is critical when dealing with political and religious questions, which are especially susceptible to non-rational thought.
Nevertheless, absolute certainty is never attainable since there always exists the possibility of one (or more) unknown contrary opinions based on logical reasoning or empirical evidence.
BRSE Russell, Bertrand. Sceptical Essays. 2nd ed.,
Routledge, New York, NY 2004