"Existenz" is a key concept in the philosophy of Karl Jaspers, particularly within his existential philosophy, and it is discussed in the source _Existentialism From Dostoevsky To Sartre_ as presented by Walter Kaufmann. It is crucial to understand that for Jaspers, "Existenz" is not something that can be objectively known or scientifically investigated in the same way as other realities. According to Kaufmann's interpretation of Jaspers, "Existenz" is one of the modes of "the Encompassing which we are". The Encompassing also includes empirical existence, consciousness as such, and spirit. However, "Existenz" is distinct from these. While empirical existence, consciousness as such, and spirit appear in the world and can become objects of scientific investigation, "Existenz" is not an object and cannot be grasped as something that appears before us in the world. Instead, it is that _in which_ all other things appear to us. We do not cognize it as an object; rather, we become aware of it as a limit. "Existenz" is presented as the central point of philosophizing, reached in the awareness of potential Existenz. It is described as the fundamental origin and the condition of selfhood, without which the vastness of Being becomes meaningless. Although "Existenz" itself never becomes an object or form, it carries the meaning of every mode of the Encompassing. Initially, "Existenz" might seem like a narrowing to the uniqueness of the individual self, contrasting with the encompassing spirit. It might appear as an emptiness lodged within empirical existence, consciousness, and spirit. However, this contracted point is, in fact, the sole possible revelation of the depths of Being as historicity. The self can become genuinely certain of itself in all modes of the Encompassing only as "Existenz". When contrasted with consciousness as such, "Existenz" is seen as the hidden ground within us to which Transcendence is first revealed. The Encompassing which we are exists only in relation to something other than itself. Just as consciousness is conscious only when it has an objective being before it, so too, we are "Existenz" only when we know Transcendence as the power through which we genuinely are ourselves. The "Other" for consciousness as such is the being which is in the world, while the "Other" for "Existenz" is Transcendence. This distinction becomes clear through the inwardness of "Existenz". Without "Existenz," the meaning of Transcendence is lost, becoming something indifferent, unknown, or merely excogitated by consciousness. Only through "Existenz" can Transcendence become present without superstition, as the genuine reality that never disappears. Further, "Existenz" is like the counterpart to spirit. Spirit is characterized as the will to become whole, whereas potential "Existenz" is the will to be authentic. Spirit is intelligible and comes to itself in the whole, but "Existenz" is unintelligible, standing by and against other Existenzen, breaking up every whole and never reaching a real totality. For spirit, a final transparency would be the origin of Being, but "Existenz" remains the irremediably dark origin even in all clarity of spirit. Spirit tends to make everything disappear into universality and totality, whereas "Existenz" is irreducibly in another, absolutely firm, irreplaceable, and thus, authentic being before Transcendence, to which it surrenders without reservation. Spirit aims to grasp the individual as an example of a universal or a part of a whole. In contrast, "Existenz," as the possibility of decision derivable from no universal validity, is an origin in time, the individual as historicity. It is the apprehension of timelessness through temporality, not through universal concepts. While spirit is historical by retrospectively representing itself as a transparent totality, "Existenz" is historical as eternity in time, as the absolute historicity of its concrete empirical existence in a spiritual opacity that is never removed—the paradox of the unity of temporality and eternity. Kaufmann suggests that when we compare "Existenz" with consciousness as such, spirit, or any other mode of the Encompassing, the same thing becomes apparent: without "Existenz," everything seems empty, hollowed out, without ground, and fake, as everything turns into endless masks, mere possibilities, or mere empirical existence. The source also emphasizes the inseparable bond between reason and "Existenz". These are the great poles of our being that encounter each other in every mode of the Encompassing. Reason should not surrender to "Existenz" to produce isolating defiance, and "Existenz" should not surrender to reason in favor of a transparency that replaces substantial reality. "Existenz" only becomes clear through reason, and reason only has content through "Existenz". Reason has an impulse to move beyond mere correctness into a living bond through the ideas of the spirit and towards "Existenz" as that which supports and gives authentic being to the spirit. Reason is oriented towards the content of "Existenz," which clarifies itself in reason and gives decisive impulses to it. Without content, reason would be mere understanding, and without "Existenz," reason is hollow, just as concepts are empty without intuition. Reason is not merely understanding but exists in the acts of potential "Existenz". Conversely, "Existenz" is also oriented towards an "Other," which is Transcendence, through which it becomes an independent cause in the world, as "Existenz" does not create itself. Without Transcendence, "Existenz" becomes sterile defiance. Oriented to reason, through whose clarity it experiences unrest and the appeal of Transcendence, "Existenz" comes into its own authentic movement under the questioning of reason. Without reason, "Existenz" is inactive and as though not there. The clarification of "Existenz" does not involve a cognitive understanding of it but rather an appeal to its potentialities. "Existentialism," when it pretends to be a discourse about a known object, errs because it should be perceiving its limits and clarifying the absolute ground instead of trying to subsume appearances under its concepts. Attempts to establish, isolate, and absolutize the Encompassing lead to the disappearance of the true Encompassing; an Encompassing that has become objective is no longer the true Encompassing. In essence, "Existenz" as described by Jaspers (through Kaufmann's interpretation) is the non-objective, hidden ground of selfhood and authenticity, which comes into play through our awareness of Transcendence and in a dynamic relationship with reason. It is the potential for being one's true self, a self that cannot be fully grasped by objective knowledge but is revealed in the individual's historical existence and their relationship to what transcends the empirical world. It is the "dark ground of selfhood, the concealment out of which I come to encounter myself and for which Transcendence first becomes real". This potential "Existenz" is also described as the will to be authentic.