These criticisms are restated in A 491-2 = B 519-20, with the further addition that in denying the existence of extended beings “the empirical idealist” removes the possibility of distinguishing between reality and dreams. This is a new criticism. Kant is no longer referring to the denial of unknowable things in themselves. He is now maintaining that only the Critical standpoint can supply an immanent criterion whereby real experiences may be distinguished from merely subjective happenings. This point is further insisted upon in the _Prolegomena_,[613] but is nowhere developed with any direct reference to Berkeley’s own personal teaching. Kant assumes as established that any such criterion must rest upon the _a priori_; and in this connection Berkeley is conveniently made to figure as a thoroughgoing empiricist. The _Critique_, on its publication, was at once attacked, especially in the Garve-Feder review, as presenting an idealism similar to that of Berkeley. As Erdmann has shown, the original plan of the _Prolegomena_ was largely modified in order to afford opportunity for reply to this “unpardonable and almost intentional misconception.”[614] Kant’s references to Berkeley, direct and indirect, now for the first time manifest a polemical tone, exaggerating in every possible way the difference between their points of view. Only the transcendental philosophy can establish the possibility of _a priori_ knowledge, and so it alone can afford a criterion for distinguishing between realities and dreams. It alone will account for the possibility of geometrical science; Berkeley’s idealism would render the claims of that science wholly illusory. The Critical idealism transcends experience only so far as is required to discover the conditions which make empirical cognition possible; Berkeley’s idealism is ‘visionary’ and ‘mystical.’[615] Even sceptical idealism now comes in for severe handling. It may be called “dreaming idealism”; it makes things out of mere representations, and like idealism in its dogmatic form it virtually denies the existence of the only true reality, that of things in themselves. Sceptical idealism misinterprets space by making it empirical, dogmatic idealism by regarding it as an attribute of the real. Both entirely ignore the problem of time. For these reasons they underestimate the powers of sensibility (to which space and time belong as _a priori_ forms), and exaggerate those of pure understanding. “The position of all genuine idealists from the Eleatics to Berkeley is contained in this formula: ‘All cognition through the senses and experience is nothing but mere illusion, and only in the ideas of pure understanding and Reason is there truth.’ The fundamental principle ruling all my idealism, on the contrary, is this: ‘All cognition of things solely from pure understanding or pure Reason is nothing but mere illusion and only in experience is there truth.’”[616]