We have noted that the acquisition of forms in knowledge is different from the acquisition of forms in the natural, material way. Immateriality may well serve as a touchstone to differentiate neo-Thomism from other twentieth-century schools. It underlines the differences with Marxism or the empiricist and positivist strain in analytic philosophy. In so far as the neo-Thomists reach the existence of positively immaterial entities by inference, they part company with the strict phenomenological limitation to study what is directly given. We could also emphasize parallels instead of divergences. Even a thinker like Jean-Paul Sartre feels that consciousness is so different from matter that he terms it non-being.