only once and in divine understanding, the progress of knowledge now had the same origin and found itself caught up in the same empirical process of becoming (devenir) as the progression of life: 'Nature wanted the source of our know ledge to be the same as that of life; we must receive impressions in order to live; we must receive impressions in order to know';` and, in each case, the law of development is the law of combination of these elements.