Phenomenology can be understood generally to be the study of phenomena as they are presented through intuition to consciousness by what is called the “intentional act.” In Ideas, Husserl gives the following account of what is meant by intuition:
Empirical intuition, more specifically sense experience, is consciousness of an individual object, and as an intuiting agency ‘brings it to givenness’: as perception, to primordial givenness, to the consciousness of grasping the object in ‘a primordial way’, in its ‘bodily’ selfhood. On quite similar lines essential intuition is the consciousness of something, of an ‘object’, a something towards which its glance is directed, a something ‘self-given’ within it; but which can then be ‘presented’ in other acts, vaguely or distinctly thought, made the subject of true and false predications –as is the case with every ‘object’ in the necessarily extended sense proper to Formal Logic…This essential insight is intuition, and if it is insight in the pregnant sense of the term, and not a mere, and possibly a vague representation, it is a primordial dator Intuition, grasping the essence in its ‘bodily’ self-hood.
Consciousness is essentially this intentional activity and nothing else. Therefore, Sartre begins his own discussion of ontology with an analysis of consciousness, the starting point for all phenomenological investigation. Sartre is justified in calling his own philosophy “ontological” in that he seeks to substantiate the objects of experience with “being.” He is seeking to destroy the dichotomy between appearance and reality and claim that it is the object as appearance that exists. It is the appearance of objects that is presented to consciousness. This appearance is identical to the existence of the object. For Sartre, we cannot make a distinction between an object’s essence and existence, as these are one and the same. He has rejected the possibility of Kant’s transcendental reality in favor of a phenomenal, or empirical reality in which the only things that may
“Intelligibly” said to exist are phenomena, in a substantive sense. This Sartre calls being in-itself.
2. The Object as Real and the Object as the “Ideal” Unity of its possible Appearances
Sartre says at the beginning of Being and Nothingness that, “modern thought has realized considerable progress by reducing the existent to the series of appearances which manifest it.” What he means is that any existent must have an infinite series of possible appearances and that in the intentional act of consciousness we are only aware of one among this series. This must mean that what we are consciousness of is the object, inasmuch as the aspect or appearance is necessarily of an object. Though not inconceivable, it would be nonsensical to speak of being conscious of the existent as the series of its appearances in the intentional act in which the object becomes present to consciousness. Here the principle of identity would entail that different aspects must be of the same object and that it is presented to me thus because of the finite nature of intuition: I can only be conscious of the object in one of its many possible appearances. The existent as the series of its appearances transcends consciousness in that through the intuitional act, the object is given to consciousness a priori in only one of its many possible appearances.
For us, the aspect of the object as one appearance among many is identical to the existent. Therefore, the distinction between appearance and reality, in this scheme, collapses. That the existent is only the series of its appearances may have a conceptual significance, but ontologically, what we are conscious of is the object regardless of whether it is as a totality –that is, as the “ideal” unity of its appearances– or in its finite and singular aspect as appearance. In other words, the reality of the appearance of the object to consciousness is determined by the fact that the object is the ideal unity of its possible appearances. It is interesting to consider, however, if in some sense we are conscious of the object as this unity. For only the real and actual manifestation of an object can determine its other possible appearances, and conversely, the multiplicity of possible appearances determines the appearance of the object when it is revealed to consciousness as a singular and specific appearance at a particular time and place.
For example, to have the object appear to me in a particular form gives rise within consciousness of its other possible appearances. Thus, I sense how the object would, for example, appear from another angle. In other words, the object as concretely given gives rise to the fact that the object truly is an ideal unity of its appearances. We must consider too that there is a distinction between “real” possibilities and “logical” possibility in so far as the possible appearances of an object is concerned. Can this distinction hold? 
The existent as the totality of its appearances is not a real entity, rather a conceptual construct, which as such has a true object to which it refers. In this case, the referent is the object as the ideal unity or totality of its appearances, and as such, it also is an intentional object for consciousness, though specifically for knowing-consciousness. That the for-itself only grasps phenomena in its finite aspect shows some correlation to the finitude of consciousness in general. Sartre characterizes consciousness as an endless activity of negation. Through intention, consciousness negates itself by the fact that there could not be consciousness if it were not at one and the same time separated from the object and conscious of itself as being so separated. Consciousness is not its object and it is also aware of itself as being distinct from the object.
3. Negation and the Intentionality of Consciousness
Every act of consciousness consists of a double negation. At the most fundamental level of consciousness for-itself it is both what it is not and not what it is; i.e., a consciousness of something outside it as well as self-consciousness. Consciousness for-itself “negates nothingness” in that consciousness is separated from its object, thereby isolating the object as such, and “reveals” that the object is a phenomenon of being and that it therefore exists as a being in-itself, in other words, as something which in this particular instant the for-itself is not. The second level of negation consists of the self-awareness of consciousness of this distance between itself and the world.
To be aware of something is doubly negating. Every intending act is positionally aware of the object it posits and non-positionally aware of itself as awareness. Sartre distinguishes the two by putting the second “of” in parentheses: Consciousness of an object is also consciousness (of) itself. To put it another way: All consciousness is of something and at the same time self-consciousness.
Sartre’s incessant characterization of consciousness as “nothingness” and its negating activity is philosophically important, and central to the phenomenology of consciousness despite its somewhat romantic connotations. It is contradictory to suggest, as Sartre, that the regions of being emerge from consciousness if it is essentially nothing. For if these relations emerge from it, and, as it were, held within it, then we must reckon this with the fact that this function is part of the structure of consciousness. Being shares this structure in that consciousness constitutes one of its regions, i.e., the for-itself. This does not mean that nothingness is a region of being, but that the for-itself is the being through which nothingness arises within being.
Sartre’s description of negatité, or the negating activity of consciousness illustrates this state of affairs quite well; however, this concept may actually work contrary to his interest if we observe that his entire ontological enterprise rests upon a fundamental negation. In a greater sense, ontology as a whole is something of a negation of being in-itself, and therefore, as soon as any aspect of being in-itself becomes the object of reflective-consciousness it can no longer be identified with what it is itself. There is a falsifying element that saturates the moment in which the object appears to us as a particular, and, by definition, limited thing. This is what Sartre calls the “transphenomenality” of being. I will return to this point in more detail shortly.
However, I believe that Sartre perhaps purposely, overlooks this problem and never actually confronts it. Does Sartre find himself in the same dilemma as Kant did before him? If he does, then there is no possible way for him to save himself because he has characterized consciousness as essentially negativity. If it is only through negativity that we inevitably create the “world” and understand the nature of its being, then all being as it is present to consciousness is of negative value because it is different than being is itself. Being itself is not identical to our representation of it. 
I make a distinction between being itself and being in-itself. Sartre seems to treat these distinct concepts synonymously. Being itself refers to the totality of being, of which we can say nothing other than it is. Being in-itself is the being of all phenomena as they appear to consciousness. Being in-itself is a “region” of being which is only made possible through the existence of the for-itself, or consciousness, which in turn finds its own existential ground within being as a whole, that is, being itself.
We do not, of course, exist within a representation but within being, and thus we “appropriate” being. This is the means by which man effects his fundamental relation to being, and in so doing he makes “the world a synthetic complex of instrumental realities.”
[…] Man makes himself known in terms of this complex, which he is. [This means that] “Human reality” springs forth invested with being and “finds itself” (sich befinden) in being –and also that human reality causes being, which surrounds it, to be disposed around human reality in the form of the world.
We grasp being through the synthesizing act of representation. I make this distinction with the assumption that all agree that being in-itself is pure positivity. If ontology is actually a project of man whose consciousness is also nothingness, the activity by which consciousness is present to being is negative. Being in-itself and all its internal relations are as they are “for” consciousness. If there were no consciousness, then there would only be being, not phenomena, and it would therefore by definition be unknown and unintelligible. Being in-itself is pure positivity. It cannot be known as such by consciousness, and is, it seems to me, the object of a negatité.
Negatité is the negating activity of consciousness which originates in subjectivity. In other words, we project certain organizing concepts on to the “objective” world, (e.g., absence, change, destruction, etc.) but these projections falsify the world, or being, as it actually is itself. Sartre begs the question in that he presupposes that the “pure” description of being in-itself could be accurate, but at the heart of any description would be the possibility of falsification or “negativity.” This act of falsification may not only be possible, but necessary given the fundamental structures of consciousness and how these determine its relation to the world. We will inevitably and necessarily incorporate into any pure description of being in-itself concepts which are not inherent in being itself, but which find the origin in the for-itself. In light of these considerations, such a “pure” description of being would be impossible. And even if were possible, could we say anything about it? What would such a pure description be?  We must remember that Sartre calls negatités, transcendent realities that “indicate immediately an essential relation of human reality to the world.”
[…] They derive their origin from an act, an expectation, or a project of the human being; they [negatités] all indicate an aspect of being as it appears to the human being who is engaged in the world. The relations of man in the world, which the negatités indicate, having nothing in common with the relations a posteriori which are brought out by empirical activity. […] in order for the totality of being to order itself around us as instruments, in order for it to parcel itself into differentiated complexes which refer to one another and which can be used, it is necessary that negation rise up not as a thing among other things but as the rubric of a category which presides over the arrangement and redistribution of great masses of being in things. Thus the rise of man in the midst of the being, which “invests” him, causes a world to be discovered. But the essential and primordial moment of this rise is the negation. […] Man is the being through which nothingness comes to the world.
I hope that I have not created an unnecessary dichotomy by attributing negativity to being; however, considering the above passage, for example, it is obvious that for Sartre being and nothingness are intimately connected through the action by which consciousness “finds” itself in the world.
Returning to the discussion of whether ontology can be “objective,” I should like to say that even though being in-itself, or being as pure positivity, is posited by us as the necessary ground for the for-itself, it is only “known” indirectly as such, and so our fundamental relation to it must be negative. This is what leads me to ask whether Sartre’s entire enterprise is exactly this falsification. It seems then that in so far as there are reflective beings, if we accept Sartre’s ontology, then all knowledge of it will be negative. There is a necessary process of negation and falsification in intentionality. However, though it is through “ontology” that we discuss these distinct regions of being and so forth, we must remember that the condition of the very possibility of consciousness, and by implication, our thoughts concerning being, are presupposed by the existence of the “Being” in which we find ourselves and assume our various stances regarding it. This is being as a totality and plenitude, which cannot be contained within the various compartments and categories of our knowledge. Sartre himself informs us that being “overflows” the knowledge we have of it. Are not our attempts at formulating a fundamental ontology also subject to this “overflowing,” and seemingly ineffable, quality of being?
Sartre wants to save himself from this problem by suggesting that we do have access to brute positive being, but only pre-reflectively. Thus, here the question of being in-itself is brought out both positively and negatively. When we are precognitively aware of being in-itself, in the sense of being aware that we are conscious of something “out there” in the world, we are also simultaneously bringing about a negation. This occurs as soon as being in-itself becomes an object of cognition. I shall return to this problem, but beforehand I would like to examine what Sartre says about phenomena in general, that is, the problem of appearance and reality.
4. The phenomena of being and the being of phenomena
In Being and Nothingness there is not a clear distinction made between the existence and essence of phenomena. Sartre attempts to clarify this problem by drawing our attention to the difference between the phenomena of being and the being of phenomena. The phenomena of being are simply the means by which being is made manifest as appearance or “essence.” Sartre seems to equivocally hold that what is present to consciousness in intentionality is the object, which exists in itself, as well as the object as it is apprehended by consciousness. Sartre, then, is attempting to bridge the gap of the sensible or phenomenal object and the supersensible or noumenon object. This is, of course, Kant’s problem. However, Sartre has his own unique way of attempting to overcome this obstacle. It is possible, though, that only seems to solve this problem. At this is probably due to his ambiguous terminology and categorizing. We shall, nevertheless, give him the benefit of the doubt, as this is the foundation for the development of his moral philosophy, which is ultimately that with which we are most concerned.
Sartre thinks that the object of reflective consciousness is phenomenal, and we logically conclude that this phenomenon is of something (being in-itself), which is not identical with the manifestation but fundamentally related to it. We must posit a being of which phenomena are, but the extent to which being is presented to consciousness, it is limited. That is, consciousness and perception are concerned with the being of phenomena, and is therefore restricted to them alone. Sartre also, however, seems to think of the phenomena of being as being in-itself.
Notwithstanding Sartre’s contention that we do not have positive access to being in -itself, we are reduced to knowledge and access to “mere” phenomena, if my schema is correct. Therefore, for the moment I shall say that the “ontological” object is apprehended foremost, and perhaps solely, as a phenomenon. In so far as the phenomenon is apprehended as an aspect of the existent, we say that it exists; but this is only on the level of phenomenal reality. This then is what is meant by the phenomena of being.
No doubt, even if we restrict ourselves to phenomenal reality, we shall be confronted with the problem of making a distinction between phenomena as existents and the impressions we have of them. The relation between objects which are constant and the sense data we have of them may vary in accuracy, etc. If Sartre does not make this distinction, then he would find himself in the unfortunate position of claiming that the objects are exactly as they appear in sensation, which would seem to be the same as saying that the objects would appear exactly as they are in-themselves, though only phenomena. We have then two orders of appearance and reality. The first holds between reality as the “being of phenomena” and the reality of the “phenomena of being.” The dichotomy occurs in the second category if we insist on a distinction between phenomena as such and our impressions of them. Is such a distinction possible? Or are not phenomena, by definition, not objective, but subjective, thereby constituting “impressions?” This distinction of course originates in empirical philosophy. For now, however, I shall concern myself only with Sartre’s categories.
What is present to consciousness is the Abschattung (adumbration), or an aspect of the object itself in the form of an appearance; that is, one among an infinite series of appearances.  There is no doubt that there is some ambiguity here. How exactly is the essence distinct from the existence of the object? And does this distinction correlate with that made between the phenomena of being and the being of phenomena?
Clearly, everyone can see the ambiguity of Sartre’s terminology. The “being of phenomena” refers to that fact that phenomena exist. It is the object, as a phenomenon, which we say, exists. The object exists for us only as a phenomenon. In short, phenomena are the substantial and concrete objects of experience. They are the instrumental particulars which make up a synthetic totality we call “the world. Apart from their existence as instruments, we can say nothing about them, as they are “in-themselves.” Thus, he insists that the objects “exist” their phenomena (using “exist” in an unusual transitive sense). Being and appearance, for Sartre, are one and the same. The phenomena of being are the same in this sense, but Sartre emphasizes the fact that phenomena are of something, i.e., being. Logically, we must posit a being that is not identical to its phenomenal manifestation, though this is only the case if we insist upon this distinction.
I believe that that “phenomena of being” refers to existence and the “being of phenomena” refer to essence, but this is because I construe these terms differently. Another ambivalence occurs within Sartre’s rejection of Husserl’s epoché, or “phenomenological reduction,” which refers to the act by which a subject, or consciousness, grasps phenomena as what it appears to be, pure essence, and avoids or “brackets” the question of their existence as such all together. This is a heuristic device that Husserl employs for a variety of reasons. However, for Sartre, this is an unfortunate turn on Husserl’s part because it posits a transcendental subject, in effect, breaking away from the “objects” themselves, and instead placing us within the lost realm of Kantian idealism.
In fact, for Sartre, the virtue of phenomenology in the first place was in its attitude that we must return to the objects “themselves.” These terms, however, can be taken to mean more or less the same thing, but then the importance of the distinction between them is lost. It does seem that both of these terms refer sometimes to one definition and sometimes another. To say the least, the terms are confusing.
If we agree with Sartre and say that the existent is the totality of its manifestations (appearances) then we must question his belief that these manifestations are the essence of the object. Sartre says that essence, “is an ‘appearing’ which is no longer opposed to being but on the contrary is a measure of it.” He continues: […] “the being of an existent is exactly what it appears.”
We could say that the existent is really an essence, and one of the properties it must have is existence, or “being.” This, however, Sartre would reject. There is a danger, though, in suggesting, as Sartre does, that essence is a measure of existence, and, it seems, vice-versa. A circular argument develops when we suggest that things are, as they appear to be, and that they appear as they are. When closely examined we will see that appearance and existence cannot be arguments attesting to the other without begging the question. Nevertheless, this ambiguity is at the foundation of Sartre’s ontology. This leads me to question whether one can successfully develop ontology from phenomenology. Perhaps we find ourselves again in the midst of the original dualism of appearance and reality. 
If the “content” of consciousness is, in some sense, the essence of the object, with the qualification that this essence gives us its existence (as though by sleight-of-hand), then we must reexamine the possible conclusion that what is actually presented to consciousness in such circumstances is being in-itself. This problem is somewhat curtailed by what Sartre calls transphenomenality.
Transphenomenality “refers to the fact that Being although co-extensive with its appearance is not limited to it, that Being surpasses the knowledge we have of it and provides the basis for such knowledge.” Being, in short, is “revealed” to us as phenomena, but it is not limited to them. In so far as being is revealed, it is the basis of empirical knowledge. It is the existent as a phenomenon that is the object of consciousness; and the object as such, therefore, is that which we can know. Being can be revealed as phenomena only to a conscious subject, and therefore without the existence of consciousness there would be no phenomenal reality.
It is only in so far as being is transphenomenal in this sense, and therefore in itself logically and ontologically independent of consciousness (or minds), that we can speak about being as it exists in-itself; that is, being as it exists apart from human consciousness and experience.
 p. 49, Edmund Husserl, Ideas: General Introduction to Pure Phenomenology, trans. W.R. Boyce Gibson, Macmillan, 1931
 This includes other human beings as “objects.”
 Ibid. p.3. Here “modern thought” refers to the philosophy of Husserl; that is, “phenomenology.”
 It should be noted, however, that a principle of association based upon prior experience provides a logical basis for predicting an object’s probable, rather than possible, future appearances. In other words, the “ideal” unity of the object as the totality of its possible appearances may have much to do with our past experiences of the object, and therefore takes its root in a “habit” of the mind and our beliefs. This is similar, for example, to Hume’s epistemology.
 In other words, everything is “logically” possible, whereas “real” possibilities are based upon probability, and therefore, our past experiences. This distinction may not seem philosophically important at first glance; however, in the context of the problem of appearance and reality it is imperative that we address this issue lest we find ourselves within that particular trap of skepticism in which one can not claim to know anything about objects, their phenomenal manifestation, and particularly, their predictability and contiguity in so far as our perceptions of them are concerned.
 I shall clarify the difference between consciousness as such and knowing-consciousness in the next chapter.
 p. 19, Hazel E. Barnes, “Sartre’s Ontology” in The Cambridge Companion to Sartre,
ed. Christina Howells,CambridgeUniversityPress, 1992
 Here, the term “value” refers to the certitude granted by experience. Are our perceptions of the world corrigible or not? Or does consciousness, through its negativity, falsify all our experiences such that we never “accurately” experience the world as it is in itself?
 p.51, Being and Nothingness
 The reader will note the transcendental import of this question, which in many ways suggests a strong connection between the implications of Sartre’s ideas and Kant’s explicit attempt to explain the conditions of absolute knowledge in the Critique of Pure Reason. The similarities of this unlikely pair will be dealt with throughout the following chapter.
 Sartre does not use the term “cognition” as it necessarily involves a “knowing-subject,” which I believe for Sartre is merely consciousness of knowing something else; namely, the object of knowledge and therefore the object of the consciousness of being this knowledge. Thus, he maintains the primordial relation between consciousness and its object, whatever mode of consciousness it may be (viz. hating-consciousness, loving-consciousness, knowing-consciousness, hungry-consciousness). What is interesting here is to consider how the emotion directed toward a specific object when we are conscious of it alters that the “appearance” of that subject. However, this is a question that will not be addressed here.
 Once again I will mention how remarkably this line of thought resembles the transcendental idealism espoused by Kant in the Critique, but Sartre, strictly speaking, never mentions the existence of noumena. Consider, for example, that the object apart from its phenomenal reality is essentially Kant’s transcendental object X.
 Here we are only discussing the existence of the objects of consciousness. The existence of the for-itself, according to Sartre, necessarily preexists its essence. The case is not necessarily the same for objects.
 Sartre would of course see this as a false dichotomy.
 It is this author’s belief, however, that even if there were no human life on earth, for example, phenomenal reality could still exist (at some level) if there were conscious animal life. However, to speculate about how similar or dissimilar such a “reality” could be compared with what we as conscious beings consider real is futile. It is an interesting problem which, unfortunately, Sartre does not address in his work. It is most likely, however, that Sartre would say something to the effect that animals are not conscious in the same manner as human beings are, the former only being capable of “sentiment” of self which is distinct from self-consciousness, man being capable of the latter. This is, of course, Hegel’s view. However, this does not address the problem of how being appears to animals. Notwithstanding this distinction, being must appear to animals –which are, after all, conscious and sentient beings, in its phenomenal aspect. The being of phenomena is presupposed, it seems, if there are any conscious beings whatever who live and dwell in the world, which in effect, is transformed into a world of “experience.”