" On the other hand, the moral law, although it gives no such prospect, does provide a fact absolutely inexplicable from any data of the world of sense or from the whole compass of the theoretical use of reason, and this fact points to a pure intelligible world―indeed, it defines it positively and enable us to know something of it, namely a law.This law gives to the sensible world, as sensuous nature (as this concerns rational beings), the form of an intelligible world, i.e., the form of supersensuous nature, without interfering with the mechanism of the former. Nature, in the widest sense of the word, is the existence of things under laws. The sensuous nature of rational beings in general is their existence under empirically conditioned laws, and therefore it is, from the point of view of reason, heteronomy. The supersensuous nature of the same beings, on the other hand, is their existence according to laws which are independent of all empirical conditions and which therefore belong to the autonomy of pure reason. And since the laws, according to which the existence of things depends on cognition, are practical, supersensuous nature, so far as we can form a concept of it, is nothing else than nature under the autonomy of the pure practical reason. The law of this autonomy is the moral law, and it, therefore, is the fundamental law of supersensuous nature and of a pure world of the understanding, whose counterpart must exist in the world of sense without interfering with the laws of the latter. The former could be called the archetypal world (*natura archetypa*) which we know only by reason; the latter, on the other hand, could be called the ectypal world (*natura ectypa*), because it contains the possible effect of the idea of the former as the determining ground of the will."―from_Critique of Practical Reason_. Translated, with an Introduction by Lewis White Beck, p. 44. "
" We also find *physics*, in the widest sense of the word, concerned with the explanation of phenomena in the world; but it lies already in the nature of the explanations themselves that they cannot be sufficient. *Physics* is unable to stand on its own feet, but needs a *metaphysics* on which to support itself, whatever fine airs it may assume towards the latter. For it explains phenomena by something still more unknown than are they, namely by laws of nature resting on forces of nature, one of which is also the vital force. Certainly the whole present condition of all things in the world or in nature must necessarily be capable of explanation from purely physical causes. But such an explanation―supposing one actually succeeded so far as to be able to give it―must always just as necessarily be burdened with two essential imperfections (as it were with two sore points, or like Achilles with the vulnerable heel, or the devil with the cloven foot). On account of these imperfections, everything so explained would still really remain unexplained. The first imperfection is that the *beginning* of the chain of causes and effects that explains everything, in other words, of the connected and continuous changes, can positively *never* be reached, but, just like the limits of the world in space and time, recedes incessantly and *in infinitum*. The second imperfection is that all the efficient causes from which everything is explained always rest on something wholly inexplicable, that is, on the original *qualities* of things and the *natural forces* that make their appearance in them. By virtue of such forces they produce a definite effect, e.g., weight, hardness, impact, elasticity, heat, electricity, chemical forces, and so on, and such forces remain in every given explanation like an unknown quantity, not to be eliminated at all, in an otherwise perfectly solved algebraical equation. Accordingly there is not a fragment of clay, however little its value, that is not entirely composed of inexplicable qualities. Therefore these two inevitable defects in every purely physical, i.e., causal, explanation indicate that such an explanation can be only *relatively* true, and that its whole method and nature cannot be the only, the ultimate and hence sufficient one, in other words, cannot be the method that will ever be able to lead to the satisfactory solution of the difficult riddles of things, and to the true understanding of the world and of existence; but that the *physical* explanation, in general and as such, still requires one that is *metaphysical*, which would furnish the key to all its assumptions, but for that very reason would have to follow quite a different path. The first step to this is that we should bring to distinct consciousness and firmly retain the distinction between the two, that is, the difference between *physics* and *metaphysics*. In general this difference rests on the Kantian distinction between *phenomenon* and *thing-in-itself*. Just because Kant declared the thing-in-itself to be absolutely unknowable, there was, according to him, no *metaphysics* at all, but merely immanent knowledge, in other words mere *physics*, which can always speak only of phenomena, and together with this a critique of reason which aspires to metaphysics."―from_The World as Will and Representation_. Translated from the German by E. F. J. Payne. In Two Volumes, Volume II, pp. 172-173 "
" In Leibniz we can already find the striking observation that *cogitatur ergo est* is no less evident than *cogito ergo sum*. Naturally, *est* here does not mean existence or reality but being of whatever kind and form, including even ideal being, fictive being, conscious-being [*Bewusst-Sein*], etc. However, we must go even beyond this thesis of Leibniz. The correlate of the act of *cogitatio* is not, as Leibniz said, being simply, but only that type of being we call "objectifiable being." Objectifiable being must be sharply distinguished from the non-objectifiable being of an act, that is, from a kind of entity which possesses its mode of being only in performance [*Vollzug*], namely, in the performance of the act. "Being," in the widest sense of the word, belongs indeed to the being-of-an-act [*Akt-Sein*], to *cogitare*, which does not in turn require another *cogitare*. Similarly, we are only vaguely "aware" of our drives [*Triebleben*] without having them as objects as we do those elements of consciousness which lend themselves to imagery. For this reason the first order of evidence is expressed in the principle, "There is something," or, better, "There is not nothing." Here we understand by the word "nothing" the negative state of affairs of not-being in general rather than "not being something" or "not being actual." A second principle of evidence is that everything which "is" in any sense of the possible kinds of being can be analyzed in terms of its character or essence (not yet separating its contingent characteristics from its genuine essence) and its existence in some mode. With these two principles we are in a position to define precisely the concept of knowledge, a concept which is prior even to that of consciousness. Knowledge is an ultimate, unique, and underivable ontological relationship between two beings. I mean by this that any being A "knows" any being B whenever A participates in the essence or nature of B, without B's suffering any alteration in its nature or essence because of A's participation in it. Such participation is possible both in the case of objectifiable being and in that of active [*akthaften*] being, for instance, when we repeat the performance of the act; or in feelings, when we relive the feelings, etc. The concept of participation is, therefore, wider than that of objective knowledge, that is, knowledge of objectifiable being. The participation which is in question here can never be dissolved into a causal relation, or one of sameness and similarity, or one of sign and signification; it is an ultimate and essential relation of a peculiar type. We say further of B that, when A participates in B and B belongs to the order of objectifiable being, B becomes an "objective being" ["*Gegenstand"-sein*]. Confusing the being of an object [*Sein des Gegenstandes*] with the fact that an entity is an object [*Gegenstandssein eines Seienden*] is one of the fundamental errors of idealism. On the contrary, the being of B, in the sense of a mode of reality, never enters into the knowledge-relation. The being of B can never stand to the real bearer of knowledge in any but a causal relation. The *ens reale* remains, therefore, outside of every possible knowledge-relation, not only the human but also the divine, if such exists. Both the concept of the "intentional act" and that of the "subject" of this act, an "I" which performs acts, are logically posterior. The intentional act is to be defined as the process of becoming [*Werdesein*] in A through which A participates in the nature or essence of B, or that through which this participation is produced. To this extent the Scholastics were right to begin with the distinction between an *ens intentionale* and an *ens reale*, and then, on the basis of this distinction, to distinguish between an intentional act and a real relation between the knower and the being of the thing known." ―from_Idealism and Realism_ "