In sociology of scientific knowledge, Planck’s principle is the view that scientific change does not occur because individual scientists change their mind, but rather that successive generations of scientists have different views.
The reason for the name is the statements by Max Planck:[1]
A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it
— Max Planck, Scientific autobiography, 1950, p. 33