ABSTRACT
Whittaker, R.H. There are those who consider questions in sciencewhich have no unequivocal experimentally determined answer scarcely worth discussing. Such feeling, along with conservatism, may have been responsible for the long and almost unchallenged dominance of the system of two kingdomsplants and animals-in the broad classification of organisms. The unchallenged position of these kingdoms has ended, however; alternative systems are being widely considered.
