Here is what another economist, a man who not only has been prominent in economic circles but is, in my view, a much better economist than Krugman ever could be, has to say about Samuelson and Krugman's remarks:
Samuelson 1948 still the standard we need today. Pathetic.
Krugman thinks Samuelson's merely playing with ideas, as opposed to seeking the (closest attainable approximation of the) truth, was a virtue. To me it was a fatal flaw. He was very, very clever, in the way that a really bright boy can solve all sorts of mathematical puzzles without knowing anything at all about how the real world works.