With Plato Philosophy likewise commenced to devote more attention to the understanding of what is further determined, and in this way the matter of knowledge began to fall into divisions. In the Timæus the Idea thus makes its appearance as expressed in its concrete determinateness, and the Platonic Philosophy of Nature hence teaches us to have a better knowledge of the reality of the world; we cannot, however, enter into details, and if we did, they have little interest. It is more especially where Plato treats of physiology that his statements in no way correspond with what we now know, although we cannot fail to wonder at the brilliant glimpses of the truth there found, which have been only too much misconceived by the moderns. Plato derived a great deal from the Pythagoreans; how much is theirs, however, cannot be satisfactorily determined. We remarked before (p. 14) that the Timæus is really the fuller version of a Pythagorean treatise; other would-be wise persons have indeed said that the treatise is only an abstract made by a Pythagorean of the larger work of Plato, but the first theory is the more probable. The Timæus has in all times been esteemed the most difficult and obscure of the Platonic dialogues. This difficulty is due in part to the apparent mingling of conceiving knowledge and ordinary perception already mentioned (p. 20), just as we shall presently find an intermingling of Pythagorean numbers; and it is due still more to the philosophic nature of the matter in hand, of which Plato was as yet unconscious. The second difficulty lies in the arrangement of the whole, for what at once strikes one is that Plato repeatedly breaks off the thread of his argument, often appearing to turn back and begin again from the beginning.[45] This moved critics such as August Wolff and others, who could not understand it philosophically, to take the Timæus to be an accumulation of fragments put together, or else to be several works which had only been loosely strung together into one, or into the Platonic portion of which much that is foreign had been introduced. Wolff accordingly thought it was evident from this that the dialogue, like Homer’s poems, had been, in its first form, spoken and not written. But although the connection seems unmethodical, and Plato himself makes what maybe called copious excuses for the confusion, we shall find how the whole matter really falls into natural divisions, and we shall also find the deep inward reason which makes necessary the frequent return to what apparently is the beginning.