His main contribution was his strong opposition to quackery in psychology, but then not the whole psychology is quackery. In the hindsight, he should have been more careful in drawing a distinction between the two. In a way, his criticism of psychology resembles Graeber's criticism of economics - bot focus on quackery as if it were the whole discipline.
So the lesson to be learned is to hedge criticism against possible advances in actual science.
-- Wojtek
"An anarchist is a neoliberal without money."