SEC. 30. It would be easy to select from Spinoza, that master of reasonings apparently very exact but really very loose, many good instances of confused samenesses. I shall confine myself to a single one, his argument to prove that every substance is necessarily infinite. It is the eighth proposition in Part I of the Ethics. "There cannot be more than one substance with the same attribute, and this exists of its own nature. It belongs, then, to its nature to exist either as finite or as infinite. But it cannot be finite, for then it would have to be limited by another of the same kind, which would also necessarily exist; there would then be two substances with the same attribute, which is absurd. It is, therefore, infinite."[55] [55] _Substantia unius attributi non nisi unica existit, et ad ipsius naturam pertinet existere. Erit ergo de ipsius natura vel finita vel infinita existere. At non finita. Nam deberet terminari ab alia eiusdem naturæ, quæ etiam necessario deberet existere; adeoque darentur duæ substantiæ eiusdem attributi, quod est absurdum. Existit ergo infinita_; q. e. d.--_Ethices, Pars prima; VIII. Omnis substantia est necessario infinita._ Leipzig, 1875, p. 84. Among its defects this argument includes a confusion of sameness in sense fourth with sameness in sense first. Attribute Spinoza has defined as that which is conceived as the essence of substance. Mode is a modification of substance. Two substances, he has argued, cannot be distinguished from each other by their modifications, for substance is prior to its modifications, and we may set these aside and consider it as it is in itself. Substances cannot then, be distinguished except by their attributes; and if the attribute be the same, how can we say that there are two substances? There cannot, consequently, be two substances with the same attribute. But, the argument continues, since there cannot be two substances with the same attribute, every substance must be infinite; for, to be finite, a thing must be limited by something: and nothing can be limited except by a thing of the same kind (for example, a material thing cannot be limited by a thought). But if a thing be limited by another thing of the same kind, the thing limited and the thing limiting have the same attribute. It follows that they are not two things, but one. The thing in question is not limited but infinite.