1. It is assumed, without proof, that the entire system of Being may be ranked under the three categories of Substance, Attributes, and Modes. It is assumed, equally without proof, that there can be no substance which is not self-existent, necessary, and eternal, and that every being which does not possess these properties must be only a "mode" or affection of another being to whom they belong. It is further assumed, also without proof, that _extension_ and _thought_ are necessary "attributes" of the one self-existent "substance," each of the two exhibiting only a different aspect of his eternal essence, while both are equally essential and equally infinite. And, finally, it is assumed, still without proof, that Nature comprehends a twofold series of existences, distinct from each other, but developed, as it were, in parallel lines,--Corporeal and Intellectual beings, which correspond respectively to the Divine attributes of extension and thought,--which partake of the essential nature of these attributes, but exhibit them in finite and transient forms, as mere modes or manifestations of the one infinite "substance." These are some of the fundamental assumptions on which he proceeds; they are not proved, nor even attempted to be proved; for, although several are stated in the form of distinct propositions, and accompanied with a formal demonstration, the most cursory inspection of the pretended proof is sufficient to show that it consists entirely in a series of _deductions from principles previously assumed_, and that its validity must ultimately rest on the _definitions_ in which these principles are embodied.