Philosophical thought and knowledge, with that diversity of illustration and variety in method which follows from its universality, is in this respect somewhat in the same case with poetry. Of all the imitative arts poetry alone embraces and by its nature is intended to embrace the whole man. It is therefore free to borrow its similes or colours and manifold figurative expressions from every sphere of life and nature, and to take them now from this now from that object, as on each occasion appears most striking and appropriate....In the same way, philosophy is not confined to any one invariable and immutable form. At one time it may come forward in the guise of a moral, legislative, or a judicial discussion; at another, as a description of natural history. Or, perhaps, it may assume the method of an historical and genealogical development and derivation of ideas as best fitted to exhibit the thoughts which it aims at illustrating in their mutual coherence and connexion.....Every method and every scientific form is good; or at least, when rightly employed, is good. But no one ought to be exclusive. No one must be carried out with painful uniformity, and with wearying monotony be invariably followed throughout.
Friedrich von Schlegel, Philosophy of Life, pp. 188-189.