The only Thought which Philosophy brings with it to the contemplation of History, is the simple conception of Reason; that Reason is the Sovereign of the World; that the history of the world therefore, presents us with a rational process. This conviction and intuition is a hypothesis in the domain of history as such. In that of Philosophy it is no hypothesis. It is there proved by speculative cognition, that Reason — and this term may here suffice us, without investigating the relation sustained by the Universe to the Divine Being, — is Substance, as well as Infinite Power; its own Infinite Material underlying all the natural and spiritual life which it originates, as also the Infinite Form, — that which sets this Material in motion. On the one hand, Reason is the substance of the Universe; viz. that by which and in which all reality has its being and subsistence. On the other hand, it is the Infinite Energy of the Universe; since Reason is not so powerless as to be incapable of producing anything but a mere ideal, a mere intention — having its place outside reality, nobody knows where; something separate and abstract, in the heads of certain human beings. It is the infinite complex of things, their entire Essence and Truth. It is its own material which it commits to its own Active Energy to work up; not needing, as finite action does, the conditions of an external material of given means from which it may obtain its support, and the objects of its activity. It supplies its own nourishment and is the object of its own operations. While it is exclusively its own basis of existence, and absolute final aim, it is also the energising power realising this aim; developing it not only in the phenomena of the Natural, but also of the Spiritual Universe — the History of the World. That this "Idea" or "Reason" is the True, the Eternal, the absolutely powerful essence; that it reveals itself in the World, and that in that World nothing else is revealed but this and its honour and glory — is the thesis which, as we have said, has been proved in Philosophy and is here regarded as demonstrated. This excerpt is from which author's book?