§ 15. “As in Nature sense is the servant of imagination; imagination of memory; memory of reason; so in teaching arts and sciences we must set these faculties a-work in this order towards their proper objects in everything which is to be taught. Whence this will follow, that as the faculties of Man’s soul naturally perfect each other by their mutual subordination; so the Arts which perfect those faculties should be gradually suggested: and the objects wherewith the faculties are to be conversant according to the rules of Art should be offered in that order which is answerable to their proper ends and uses and not otherwise.” § 16. In this and much else that Dury says we see a firm grasp of the principle that the instruction given should be regulated by the gradual development of the learner’s faculties. The three sources of our knowledge, says he, are—1. Sense; 2. Tradition; 3. Reason; and Sense comes first. “Art or sciences which may be learnt by mere sense should not be learnt any other way.” “As children’s faculties break forth in them by degrees to be vigorous with their years and the growth of their bodies, so they are to be filled with objects whereof they are capable, and plied with arts; whence followeth that while children are not capable of the acts of reasoning, the method of filling their senses and imaginations with outward objects should be plied. Nor is their memory at this time to be charged further with any objects than their imagination rightly ordered and fixed doth of itself impress the same upon them.” After speaking of the common abuse of general rules, he says: “So far as those faculties (viz., sense, imagination, and memory) are started with matters of observation, so far rules may be given to direct the mind in the use of the same, and no further.” “The arts and sciences which lead us to reflect upon the use of our own faculties are not to be taught till we are fully acquainted with their proper objects, and the direct acts of the faculties about them.” So “it is a very absurd and preposterous course to teach Logick and Metaphysicks before or with other Humane Sciences which depend more upon Sense and Imagination than reasoning” (p. 46). § 17. In all this it seems to me that the worthy Puritan, of whom nobody but Dr. Barnard and Professor Masson has ever heard, has truly done more to lay a foundation for the art of teaching than his famous contemporaries Milton and Locke. § 18. Another writer of that day better known than Dury and with far more power of expression was Sir William Petty. He is the “W.P.,” who in an Epistle “to his honoured friend Master Samuel Hartlib,” set down his “thoughts concerning the advancement of real learning” (1647). This letter is to be shown only “to those few that are Reall Friends to the Designe of Realities.”[103]