The Remaining Works of Benedictus de Spinoza

But this whole unity of subject with object is not necessarily of such a kind except when the subject is thinking. Furthermore, every deduction of derived principles or special reasons from one absolute and inherently true principle does not occur except in the realm, so to speak, of reason or formal truth. Finally, that necessary identification of diverse things, without which there would be neither affirmation nor negation, also pertains to the form of thinking. But whether two objects, which are present in the mind and are currently considered as one by a given thinker in a certain respect—that is, are conceived under the form of unity—are one by their own nature (which we are forced to attribute to those things we cannot help but think of with the notion of existence), or whether they merely seem to be one to the thinker at this moment, that thinker indeed, however much he may be a subject-object (that is, even though he thinks from his own subjective unity with the object), cannot decide and determine while judging so formally. Everyone proclaims or feels that this depends, of course, on the matter; but the matter (I mean the internal matter of thinking) does not depend on that mode by which it is now thought of by this or that person, that is, reduced from diversity to unity. Rather, the ideal object—that is, that which exists in the mind and because of which the mind can rightly be called a subject-object—is subject to necessity or the reality of its own nature whenever it presents itself to the mind to be thought of with existence, in such a way that the ideal object cannot be formally identified with another in vain and erroneously, unless it must be identified by the reality of its own nature.