操作主义:斯金納(B.F.Skinner)同赫尔在一个方面是完全对立的。赫尔主要努力于先验地确立公設,并用經验材料來检验从公設所推論的定理。斯金納則避免公設。他宁愿从經验材料开始,如果有必要,逐漸走向暫时的概括。赫尔代表心理学研究的演繹法,斯金納代表培根、約翰·穆勒等所发展的 Operationalism: B.F. Skinner and Hull are diametrically opposed in one respect. Hull worked mainly a priori to establish the public and used empirical data to test the theorem deduced from the public. Skinner avoided public works. He would rather start with empirical material and, if necessary, gradually move toward a tentative overview. Hull on behalf of psychology research deductive method, Skinner on behalf of Bacon, John Mill and other developed