For as in the previous examples 'to be' and 'not to be' are additions, while the actual things that are subjects are white and man, so here 'to be' serves as subject, while 'to be possible' and 'to be admissible' are additions these determining the possible and not possible in the case of 'to be', just as in the previous cases 'to be' and 'not to be' determine the true.