On the liberal side, mostly in circles of freemasons and the Université Libre de Bruxelles, the principle of "Free Research" ("Vrij Onderzoek") gained influence, which, as it was interpreted there and then, was incompatible with catholic orthodoxy. This sharpened the anti-clerical sentiment among liberals which evolved into a militant anti-Catholicism. The complete secularisation of Belgian society became the liberals' prime objective. In order to achieve this aim, they were forced to interventions of the state, since social life was completely dominated by Roman Catholic organisations. The main battleground, however, was the field of education and the academic freedom of Belgian universities, where rationalism and scientific positivism were gaining ground.