For all are brought to a conclusion either probatively or per impossibile, in both ways the first figure is formed: if they are made perfect probatively, because (as we saw) all are brought to a conclusion by means of conversion, and conversion produces the first figure; if they are proved per impossibile, because on the assumption of the false statement the deduction comes about by means of the first figure, eg in the last figure, if A and belong to every, it follows that A belongs to some B; for if A belonged to no, and belongs to every, A would belong to no C; but (as we stated)