Planck's radiation law: Act of desperation

[Saxby]

Planck's radiation law: "Act of desperation"

Why did Max Planck refer to his own radiation law (http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35774&fbodylongid=1696) as an act of desperation.

Was it because it was only mathematical and that he didn't really understand why the equation worked?

 

[LayMuon]

Probably his all other attempts at sensibly fitting a theory to experimental results failed and he went beyond well-established postulated quantization.