When the thinking mind has arrived at the mathematical truth that the circumference of a circle is the product of the diameter multiplied by _Ludolph’s_ number, it knows—unless indeed it has lost its natural candour—that it has not of itself produced this result of reasoning, but that it has recognized in it an objective reality of truth, distinct from its own thought, and has reproduced that truth in itself. And because this reproduction corresponds to the reality, it is called true cognition. Similarly, when the intellect expresses the general law of causality, namely, everything that happens has a cause, the intellect is again convinced that it has not of itself produced this result of reasoning, but has only reproduced it by assimilating to itself an objective truth which is necessarily so and cannot be otherwise, and which the mind must assimilate if it wants to think aright. This is true not only when the mind is dealing with concrete things, but also when it would give expression to general principles, as in the present instance; these, too, are not subjective projections, but are independent of the thinking subject, and are eternal laws. This view of the nature of human cognition and thought has gradually undergone an essential change, not indeed with those outside the influence of philosophical speculation, but with the representatives of modern philosophy, and those subject to its influence. Objectivism has been superseded by subjectivism. Its principle is this: cognition, imagination, and thought are not the intellectual apprehension of an objective world existing independent of us, of which we reproduce in ourselves a counterpart. No, _the mind creates its own results of reason and cognition_; the objects before us are the creatures of the imagining subject. At the utmost, we can but say that our reasoning is the manner in which a hidden exterior world appears to us. This manner must necessarily conform to the peculiarity of the subject, to his faculties and stage of development; but the exterior world as it is in itself we can never apprehend. _Descartes_, starting with the premise that consciousness is the beginning of all certainty, was the first modern philosopher to enter upon the way of subjectivism. He was followed by _Locke_, _Berkeley_, and _Kant_. It is due to them that in the modern theory of cognition the fundamental principle of idealistic subjectivism, no matter how difficult and unreasonable it may appear to an ordinary thinker, has obtained so many advocates who, nevertheless, cannot adhere to it, but contradict it at every step.