There are _a priori_ reasons, therefore, for doubting the truth of all philosophies of the sciences which tacitly proceed upon the common notion that scientific knowledge and ordinary knowledge are separate; instead of commencing, as they should, by affiliating the one upon the other, and showing how it gradually came to be distinguishable from the other. We may expect to find their generalizations essentially artificial; and we shall not be deceived. Some illustrations of this may here be fitly introduced, by way of preliminary to a brief sketch of the genesis of science from the point of view indicated. And we cannot more readily find such illustrations than by glancing at a few of the various _classifications_ of the sciences that have from time to time been proposed. To consider all of them would take too much space: we must content ourselves with some of the latest. * * * * * Commencing with those which may be soonest disposed of, let us notice first the arrangement propounded by Oken. An abstract of it runs thus:-- Part I. MATHESIS.--_Pneumatogeny_: Primary Art, Primary Consciousness, God, Primary Rest, Time, Polarity, Motion, Man, Space, Point, Line, Surface, Globe, Rotation.--_Hylogeny_: Gravity, Matter, Ether, Heavenly Bodies, Light, Heat, Fire. (He explains that MATHESIS is the doctrine of the whole; _Pneumatogeny_ being the doctrine of immaterial totalities, and _Hylogeny_ that of material totalities.) Part II. ONTOLOGY.--_Cosmogeny_: Rest, Centre, Motion, Line, Planets, Form, Planetary System, Comets.--_Stoechiogeny_: Condensation, Simple Matter, Elements, Air, Water, Earth.--_Stoechiology_: Functions of the Elements, &c. &c.--_Kingdoms of Nature_: Individuals. (He says in explanation that "ONTOLOGY teaches us the phenomena of matter. The first of these are the heavenly bodies comprehended by _Cosmogeny_. These divide into elements--_Stoechiogeny_. The earth element divides into minerals--_Mineralogy_. These unite into one collective body--_Geogeny_. The whole in singulars is the living, or _Organic_, which again divides into plants and animals. _Biology_, therefore, divides into _Organogeny_, _Phytosophy_, _Zoosophy_.") FIRST KINGDOM.--MINERALS. _Mineralogy_, _Geology_. Part III. BIOLOGY.--_Organosophy_, _Phytogeny_, _Phyto-physiology_, _Phytology_, _Zoogeny_, _Physiology_, _Zoology_, _Psychology_.