his 1958 book The Affluent Society:

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