In spite of all that one may say, nothing is so persistently and ever anew misunderstood as _Idealism_, because it is interpreted as meaning that one denies the _empirical_ reality of the external world. Upon this rests the perpetual return to the appeal to common sense, which appears in many forms and guises; for example, as an “irresistible conviction” in the Scotch school, or as Jacobi’s _faith_ in the reality of the external world. The external world by no means presents itself, as Jacobi declares, upon credit, and is accepted by us upon trust and faith. It presents itself as that which it is, and performs directly what it promises. It must be remembered that Jacobi, who set up such a credit or faith theory of the world, and had the fortune to impose it upon a few professors of philosophy, who for thirty years have philosophised upon the same lines lengthily and at their ease, is the same man who once denounced Lessing as a Spinozist, and afterwards denounced Schelling as an atheist, and who received from the latter the well-known and well-deserved castigation. In keeping with such zeal, when he reduced the external world to a mere matter of faith he only wished to open the door to faith in general, and to prepare belief for that which was afterwards really to be made a matter of belief; as if, in order to introduce a paper currency, one should seek to appeal to the fact that the value of the ringing coin also depends merely on the stamp which the State has set upon it. Jacobi, in his doctrine that the reality of the external world is assumed upon faith, is just exactly “the transcendental realist who plays the empirical idealist” censured by Kant in the “Critique of Pure Reason,” first edition, p. 369.