Conventional wisdom is the body of ideas or explanations generally accepted as true by the public and/or by experts in a field.
Origin of the termThe term is often credited to the economist John Kenneth Galbraith, who used it in his 1958 book The Affluent Society:
However, the term dates back to at least 1838. Conventional wisdom was used in a number of other works before Galbraith, occasionally in a positive or neutral sense, but more often pejoratively. However, previous authors used it as a synonym for 'commonplace knowledge'. Galbraith specifically prepended 'The' to the phrase to emphasize its uniqueness, and sharpened its meaning to narrow it to those commonplace beliefs that are also acceptable and comfortable to society, thus enhancing their ability to resist facts that might diminish them. He repeatedly referred to it throughout the text of The Affluent Society, invoking it to explain the high degree of resistance in academic economics to new ideas. For these reasons, he is usually credited with the invention and popularization of the phrase in modern usage.
Conventional wisdom is not necessarily true. It is often seen as a hindrance to the acceptance of new information, and to the introduction of new theories and explanations. Therefore it operates as an obstacle that must be overcome by legitimate revisionism. This is to say, that despite new information to the contrary, conventional wisdom has a property analogous to inertia that opposes the introduction of contrary belief, sometimes to the point of absurd denial of the new information set by persons strongly holding an outdated (conventional) view. This inertia is due to conventional wisdom being convenient, appealing and deeply assumed by the public, which hangs on to them even as they grow outdated. This inertia can last even after the paradigm has shifted between competing conventional idea sets.
Conventional wisdom may also be applied or implied in a political sense, being closely related to the phenomenon of talking points. It is used pejoratively to refer to the idea that consistently repeated statements become conventional wisdom whether they are true or not.
More generally, it refers to accepted truth that almost no one would dispute, and so it is used as a gauge (or well-spring) of normative behavior or belief, even within a professional context. One such example is conventional wisdom in 1950: even among most doctors, smoking was not considered particularly harmful to one's health. Conventional wisdom in 2011: it is. Another: It might be used in this manner discussing a technical matter such as the conventional wisdom was that a man would suffer lethal injuries if he experienced more than eighteen g-forces in an aerospace vehicle. (John Stapp shattered that myth by repeatedly withstanding far more in his research, peaking above 46 Gs).
Sometimes, people in society form conventional ideas about what other people in the past considered to be conventional wisdom. For example, take the following sentence: "It is widely believed that prior to Christopher Columbus people thought the world was flat, but in actuality, scholars of that time had long accepted that the earth is a sphere."
The above sentence is true; people today often think that Columbus discovered the world to be round, when in fact the world's roundness was already widely known by Columbus' time. However, if enough people read and believe the above sentence, the above sentence will eventually supplant the old belief (the old belief in past belief in a flat earth). The above sentence would become the new conventional wisdom. (Ironically, however, this would also turn the above sentence, the new conventional wisdom, into a false claim; because the new conventional wisdom would propose that people are confused about past beliefs in a way that they actually wouldn't be.)}