[Sidenote: Four steps in Herbart’s method of instruction.] [Sidenote: ‘Five formal steps.’] But to secure this broad range of material and to unify and systematize it, Herbart realized that it was necessary to formulate a definite method of instructing the child. This plan of instruction he wished to conform to the development and working of the human mind, and on the basis of what he conceived this activity to be, he mapped out a method with four logical steps: (1) ‘clearness,’ the presentation of facts or elements to be learned; (2) ‘association,’ the uniting of these with related facts previously acquired; (3) ‘system,’ the coherent and logical arrangement of what has been associated; and (4) ‘method,’ the practical application of the system by the pupil to new data. The formulation of this method was made only in principle by Herbart, but it has since been largely modified and developed by his followers. It was soon felt that, on the principle of ‘apperception,’ the pupil must first be made conscious of the existing stock of ideas so far as they are similar to the material to be presented, and that this can be accomplished by a review of preceding lessons or by an outline of what is to be undertaken, or by both procedures. Hence Herbart’s noted disciple, Ziller, divided the step of ‘clearness’ into ‘preparation’ and ‘presentation,’ and the more recent Herbartian, Rein, added ‘aim’ as a substep to ‘preparation.’ The names of the other three processes have been changed for the sake of greater lucidity and significance by still later Herbartians, and the ‘five formal steps of instruction’ are now given as (1) ‘preparation,’ (2) ‘presentation,’ (3) ‘comparison and abstraction,’ (4) ‘generalization,’ and (5) ‘application.’ [Sidenote: Clarified Pestalozzi’s vague principle of ‘observation’ through an ingenious psychology,] [Sidenote: and made Pestalozzi’s emphasis on the physical world a stepping-stone to history and literature.]