The philosophic conception of unity, the belief that there is no separation in either world, physical or psychical, or between either world, was always present to Froebel’s mind. “In Nature,” he writes, “every phenomenon has its sufficient foundation and its necessary consequence.” But as every philosopher would say, so Froebel said, “Separation is permitted for the observing, thinking and comparing intellect, and the outwardly representing life, and is indeed required by it, but must by no means on that account be permitted to appear in the mind which is intended to grasp and constantly to retain in its original inner union, that which is outwardly apparently separated by the thinking intellect, the reason and the life.”[71] So Professor Münsterberg, writing as a professed scientist, says, “Science is to me, not a mass of disconnected information, … but the certainty that nothing can exist outside the gigantic mechanism of causes and effects, but Science is not and cannot be, and ought never to try to be, an expression of ultimate reality.”[72] It would never have dawned on Froebel, nor would it have appealed to him, to separate his philosophy from his science, but there is no more contradiction in Froebel’s “self-activity” which is influenced from without, than there is in Professor Stout when he speaks of self-determination as included in the connotation of “activity,” and adds that until a case of “pure activity” is brought forward, we must assume that there is none. Of all his “means of play,” Froebel says: “In order, therefore, on the one hand to introduce the child to the handling of his play material, we gave him the ball, … but each of these means of play summons the child in return to self-activity, to free self-activity; to movement, to free independent movement” (zur Selbsthätigkeit, zur freien Selbsthätigkeit; zur Bewegung, zur freien, inabhängigen Bewegung).[73] APPENDIX II COMPARISON OF PLAYS NOTED BY FROEBEL WITH THE ENUMERATION GIVEN BY GROOS Much that is given in Groos’ more elaborate classification can also be found in Froebel’s suggestions, particularly where younger children are concerned. For plays coming under the heading of Playful Activity of the Sensory Apparatus, Froebel has a parallel for every kind except that of Temperature, and for this Groos has not himself found anything that can fairly be called play.