The attraction between two electrically neutral conductive plates was predicted theoretically in 1948 by Dutch theoretical physicist Hendrik Casimir..

He was then working at Philips Research Laboratories in Eindhoven, the Netherlands, being concerned in particular with the properties of colloidal solutions: viscous materials (such as some paints or mayonnaise) formed by the liquid solution of particles having a size of order of microns. The properties of such solutions, and in particular their stability, are determined by van der Waals forces. These are a class of attractive interactions occurring between neutral atoms and molecules, due to random fluctuations of their electronic clouds.
The theoretical framework used in the Forties to describe van der Waals forces was been developed a decade earlier by Fritz London and seemed to work pretty well …

… Until two other researchers from Philips, Theo Overbeek and Evert Verwey, made ​​more accurate measurements on van der Waals forces, finding that at "large" distances (of the order of tens of nanometers!) they decrease more rapidly than stated by the London theory. Overbeek realized that the discrepancy could be due to the finite speed of light (*), but wisely he recognized that its theoretical knowledge was not sufficient to treat the problem. IN THIS WAY...