In provisionally characterizing the object which serves as the theme of our investigation (the Being of entities, or the meaning of Being in general), it seems that we have also delineated the method to be employed. The task of ontology is to explain Being itself and to make the Being of entities stand out in full relief. And the method of ontology remains questionable in the highest degree as long as we merely consult those ontologies which have come down to us historically, or other essays of that character. Since the term "ontology" is used in this investigation in a sense which is formally broad, any attempt to clarify the method of ontology by tracing its history is automatically ruled out. When, moreover, we use the term "ontology," we are not talking about some definite philosophical discipline standing in interconnection with the others. Here one does not have to measure up to the tasks of some discipline that has been presented beforehand; on the contrary, only in terms of the objective necessities of definite questions and the kind of treatment which the 'things themselves' require, can one develop such a discipline. With the question of the meaning of Being, our investigation comes up against the fundamental question of philosophy. This is one that must be treated *phenomenologically*. Thus our treatise does not subscribe to a 'standpoint' or represent any special 'direction'; for phenomenology is nothing of either sort, nor can it become so as long as it understands itself. The expression 'phenomenology' signifies primarily a *methodological conception*. This expression does not characterize the what of the objects of philosophical research as subject-matter, but rather the *how* of that research. The more genuinely a methodological concept is worked out and the more comprehensively it determines the principles on which a science is to be conducted, all the more primordially is it rooted in the way we come to terms with the things themselves, and the farther is it removed from what we call "technical devices," though there are many such devices even in the theoretical disciplines. Thus the term 'phenomenology' expresses a maxim which can be formulated as 'To the things themselves!' It is opposed to all free-floating constructions and accidental findings; it is opposed to taking over any conceptions which only seem to have been demonstrated; it is opposed to those pseudo-questions which parade themselves as 'problems', often for generations at a time. Yet this maxim, one may rejoin, is abundantly self-evident, and it expresses, moreover, the underlying principle of any scientific knowledge whatsoever. Why should anything so self-evident be taken up explicitly in giving a title to a branch of research? In point of fact, the issue here is a kind of 'self-evidence' which we should like to bring closer to us, so far as it is important to do so in casting light upon the procedure of our treatise. We shall expound only the preliminary conception [Vorbegriff] of phenomenology. This expression has two components: "phenomenon" and "logos." Both of these go back to terms from the Greek: φαινόμενον and λόγος. Taken superficially, the term "phenomenology" is formed like "theology," "biology," "sociology"―names which may be translated as "science of God," "science of life," "science of society." This would make phenomenology the *science of phenomena*. We shall set forth the preliminary conception of phenomenology by characterizing what one has in mind in the term's two components, 'phenomenon' and 'logos', and by establishing the meaning of the name in which these are *put together*. The history of the word itself, which presumably arose in the Wolffian school, is here of no significance."―from_Being and Time_. Translated by John Macquarrie & Edward Robinson, pp. 49-51
It must be *possible* for the *I think* to accompany all my representations: for otherwise something would be represented within me that could not be thought at all, in other words, the representation would either be impossible, or at least would be nothing to me. That representation which can be given prior to all thought is called *intuition*, and all the manifold of intuition has, therefore, a necessary relation to the *I think* in the same subject in which this manifold of intuition is found. This representation (the *I think*), however, is an act of *spontaneity*, that is, it cannot be considered as belonging to sensibility. I call it *pure apperception*, in order to distinguish it from empirical apperception, as also from original apperception, because it is that self-consciousness which, by producing the representations, *I think* (which must be capable of accompanying all other representations, and which is one and the same in all consciousness), cannot itself be accompanied by any further representations. I also call the unity of apperception the *transcendental* unity of self-consciousness, in order to indicate that *a priori* knowledge can be obtained from it. For the manifold representations given in an intuition would not one and all be *my* representations, if they did not all belong to one self-consciousness. What I mean is that, as my representations (even though I am not conscious of them as that), they must conform to the condition under which alone they *can* stand together in one universal self-consciousness, because otherwise they would not one and all belong to me. From this original combination much can be inferred.The thoroughgoing identity of the apperception of a manifold that is given in intuition contains a synthesis of representations, and is possible only through the consciousness of this synthesis. For the empirical consciousness which accompanies different representations is itself dispersed and without reference to the identity of the subject. Such a reference comes about, not simply through my accompanying every representation with consciousness, but through my *adding* one representation to another and being conscious of the synthesis of them. Only because I am able to combine a manifold of given representations *in one consciousness* is it possible for me to represent to myself the *identity of the consciousness in these representations*, that is, only under the presupposition of some *synthetic* unity of apperception is the *analytic* unity of apperception possible. The thought that the representations given in intuition belong one and all *to me*, is therefore the same as the thought that I unite them in one self-consciousness, or can at least do so; and although that thought itself is not yet the consciousness of the synthesis of representations, it nevertheless presupposes the possibility of this synthesis. In other words, it is only because I am able to comprehend the manifold of representations in one consciousness that I call them one and all *my* representations. For otherwise I should have as many-coloured and varied a self as I have representations of which I am conscious. Synthetic unity of the manifold of intuitions, as given *a priori*, is thus the ground of the identity of apperception itself, which precedes *a priori* all *my* determinate thought. Combination, however, does not lie in the objects, and cannot be borrowed from them by perception and thus first be taken into the understanding. It is, rather, solely an act of the understanding, which itself is nothing but the faculty of combining *a priori* and of bringing the manifold of given representations under the unity of apperception; and the principle of this unity is, in fact, the supreme principle of all human knowledge."—from_Critique of Pure Reason_. Translated, edited, and with an Introduction by Marcus Weigelt, based on the translation by Max Müller, pp. 124-128
Human existence can relate to beings only if it holds itself out into the nothing. Going beyond beings occurs in the essence of Dasein. But this going beyond is metaphysics itself. This implies that metaphysics belongs to the "nature of man." It is neither a division of academic philosophy nor a field of arbitrary notions. Metaphysics is the basic occurrence of Dasein. It is Dasein itself. Because the truth of metaphysics dwells in this groundless ground it stands in closest proximity to the constantly lurking possibility of deepest error. For this reason no amount of scientific rigor attains to the seriousness of metaphysics. Philosophy can never be measured by the standard of the idea of science.If the question of the nothing unfolded here has actually questioned us, then we have not simply brought metaphysics before us in an extrinsic manner. Nor have we merely been "transposed" to it. We cannot be transposed there at all, because insofar as we exist we are always there already. "For by nature, my friend, man's mind dwells in philosophy" (Plato, Phaedrus, 279a). So long as man exists, philosophizing of some sort occurs. Philosophy―what we call philosophy―is metaphysics getting under way, in which philosophy comes to itself and to its explicit tasks. Philosophy gets under way only by a peculiar insertion of our own existence into the fundamental possibilities of Dasein as a whole. For this insertion it is of decisive importance, first, that we allow space for beings as a whole; second, that we release ourselves into the nothing, which is to say, that we liberate ourselves from those idols everyone has and to which he is wont to go cringing; and finally, that we let the sweep of our suspense take its full course, so that it swings back into the basic question of metaphysics which the nothing itself compels: 'Why are there beings at all, and why not rather nothing?"―from_What is Metaphysics?_