Thanks to Jon et al, I am now reading this Krugman. Today’s piece indicates he knows its true because of his peers. 

here:
” Corporations followed his lead, pouring a steady stream of money into
think tanks that created a sort of parallel intellectual universe, a
world of “scholars” whose careers are based on toeing an ideological
line, rather than on doing research that stands up to scrutiny by their
peers.”
 

and here: ” Finally, the self-policing
nature of science – scientific truth is determined by peer review, not
public opinion – can be exploited by skilled purveyors of cultural
resentment.” 

 
Thank God for alternative methods of education.