From the time of Plato and Aristotle, philosophy had been set up as the “science” of Being. Since then and up until Hegel, the problem of Being (das Sein) was at the foundations of philosophy. Indeed, Heidegger agrees that the question of Being is the only issue in philosophy.
What does this mean? The Being that forms the subject matter of philosophy is the Being of beings (das Sein des Seienden), that is, the basic reason or ground on which a “thing that is” comes to be a “thing that is. ” But what does it mean to make an issue of this ground of being of a “thing that is”? To answer this question, we must look at what Heidegger calls the ontological difference, in virtue of which metaphysics as the study of Being comes about.
The things that surround us, no matter what they are, are all things that in some way are. For example, there is something before me now; it is a desk; it is in this room; it is made of wood; and so on. We talk about and experience this kind of thing every day. “Being,” however, is not some “thing that is”; nor is any “thing that is” “Being.,, “Being” (Sein) is not any kind of being or “thing that is” (Seiendes) . But now, if what we call beings are all “things that are,” then that is all there is. If not, there would only be “nothing.”
Thus when someone says “Being,” we do not know what to think of. At the same time, we are constantly thinking and talking about “Being.”
We say things like: here is something (a thing that is) rectangular; it is a desk; it is in this room; and so forth. We already understand the “is.” Or rather, understanding immediately takes place (Verstiindnis versteht sich) .The meaning of the “is” is not grasped conceptual ly (begriffen); somehow it is understood and yet its meaning remains hidden.
Without this kind of immediate understanding we would not be able to exist in the world of “beings.” We ourselves are also “beings” who exist in the world amidst various other beings, but we differ from everything else in that we are beings who have an u nderstanding of the being of things and of ourselves as “beings” in their midst. This kind of immediate understanding of Being is part and parcel of our very way of being as beings. Our being comprehendsin its structure an understanding of Being, and this accounts for our way of being in the world.
The “world” is the place in which all beings are, but is itself neither a thing nor a being. The being of the world is not something “objective,” as the being of beings is; if it were, we would have to be outside the world in order to understand it. The world is prior (in a non-temporal sense) to everything; it is the locus in which all beings come to be and which lets them be. Therefore, when we understand that all things are, and that we ourselves are, the world is already included . All these issues-that various things are, that in their being there is included the sense of “in-the-world,” that we ourselves are actually in the world, and that our being includes an understanding of Being itself-are comprehended within the understanding of Being.
The events and experiences of everyday life rest on this immediate, self-evident understanding of Being. Philosophy-in particular, metaphysics as “first philosophy” -brings this self-evidence in question and makes an issue of Being. Ordinarily, what Being is, what the world is, what human being is, and so on, are roughly understood. In philosophy, it is precisely this rough understanding that gives these matters their deeply problematic nature. Our understanding is pregnant with “something” that lies hidden behind a smokescreen of self-evidence in what Heidegger calls “everydayness.” The question of Being may arise when we try to look at ourselves and the world objectively. Or there may be times when the being of the self becomes the kind of question that breaks through our everydayness and brings into question the world and everything in it.
In such cases, “Being” is clearly differentiated from “beings” and may be questioned thematically. Unlike the ontical (ontisch) difference between one being and another, the difference between beings and Being is the ontological difference. In contrast, the immediate understanding of Being that belongs to everyday experience is pre-ontological (vorontologisch) .
Only when the ontological difference is developed out of the preontological difference is the horizon of the discipline that takes Being thematically as the issue-namely, metaphysics-opened Up.
The significance of calling metaphysics a “discipline” is best grasped by contrasting it with what is called a “worldview.” worldview makes an issue of things like God, nature, history, reason, spirit, and life. By understanding the connections among these things, it tries to think about the meaning of the world and our lives in it. In this case God, nature, and so on are all “beings,” and our existence in relation to them is also understood as a “being.”
Here the knowledge attained within a worldview is all on ticalknowledge; the “being” itself of the various beings discussed is not brought into question. A worldview demands an ontology at its basis.
This is the place of philosophy in the true sense, of metaphysics as science . A worldview itself is not a philosophy; nor are the special sciences . Knowledge of God, nature, history, and so forth constitutes disciplines such as theology, natural science, and the study of history; but these are all sciences of “beings,” and of special kinds of being s at that. Hence they are all dependent on ontology, which questions the being itself of all things that are. The question of ontological foundations does not arise from within the standpoint of science. “Being” itself is not one of the questions of science; nor, it goes without saying, is “Nothing.”s
The ontological difference in which philosophical problems of Being and Nothing are set up forms the bedrock not only of daily life and experience but also of scientific inquiry and the construction of worldviews . Philosophy’s question is precisely what to these latter is self-evident and therefore hidden from view. At the beginning of What is Metaphysics ? Heidegger mentions Hegel’s idea of the “inverted world .” Hegel writes as follows: Philosophy by its very nature is esoteric; for itself it is neither made for the masses nor is it susceptible of being cookedup for them. It is philosophy only because it goes exactly contrary to the understanding and thus even more so to “sound common sense,” the so-called healthy human understanding, which actually means the local and temporary vision of some limited generation of human beings. To that generation the world of philosophy is in and for itself a topsy-turvy, an inverted, world .
For Heidegger, too, philosophy is an inverted world; it is a world in which the ontological foundation, hidden at the ground of everydayness and science, is turned inside out. The critical question is where to look for the clue to this inversion. Heidegger seeks it in the understanding of Being that is included in what he calls Dasein-namely, within human being. This is what provides his existential philosophy with its new standpoint.