Kant's greatest merit is the distinction of appearance from the thing in itself, on the ground that the intellect stands between the things and us

The passage

Kant's greatest merit is the distinction of appearance from the thing in itself, on the ground of the showing that between the things and us there always still stands the intellect, wherefore they cannot be cognized according to what they may be in themselves.

The first sentence of the appendix. It does three things in one sentence, and the statement keeps all three: it names the distinction as Kant's, calls it his greatest merit, and gives the ground on which it rests, »auf Grund der Nachweisung, daß zwischen den Dingen und uns immer noch der Intellekt steht«, from which the »weshalb« clause draws that the things cannot be cognized as they may be in themselves. The ground is stated as Kant's showing, not as a thesis Schopenhauer puts forward on his own account here; what he makes of it on his own account is § 24 (c-schopenhauer-forms-in-consciousness-independent-of-objects) and the sentence of this appendix on the law of causality as a function of the intellect (c-schopenhauer-causality-sensation-and-space-are-subjective). The »weshalb« clause says what Kant's A 42 / B 59 says, that what objects may be in themselves »bleibt uns gänzlich unbekannt« (c-kant-things-in-themselves-unknown), and the link shares_premise_with is set between the two: »auf Grund der Nachweisung, daß ...« is the factive construction of »Er zeigte, daß ...« in nominal form, to call it a Nachweisung is to say it was shown, and the map reads the one as it reads the other (c-schopenhauer-kant-showed-laws-of-experience-not-applicable-to-derive-existence), so both statements assert that things cannot be cognized as they may be in themselves; the comparison names the pair under that premise. A reader who holds that a sentence praising a doctrine for its ground does not assert the ground may dispute the link. The same sentence stands at the head of the comparison's row on what can be said of the thing in itself (x-thing-in-itself). The attack this appendix makes on Kant's derivation (c-schopenhauer-kant-derivation-cannot-reach-thing-in-itself) comes twenty pages later and leaves this merit standing, as c-schopenhauer-only-the-derivation-is-faulty says.