What is consciousness? What is its basic and essential character? I shall suggest the following: consciousness is the feeling of being. This terse formula will need some elaboration but it is useful as a summary statement. I mean to be speaking of consciousness in the broadest sense—the kind of consciousness (sentience) found in birds, reptiles, fish, even insects, as well as humans. Mainly this is sensory consciousness, though other kinds branch out from the basic kind (presumably it was the earliest kind of consciousness to evolve). There are two sides to the characterization I propose, corresponding to feeling and being. By the latter I simply mean existence: to be conscious is to feel the existence of something. Here two historical figures come into play: Brentano and Descartes. Brentano maintained that to be conscious is to be conscious of something, generally something other than oneself, say objects in the environment. Descartes maintained that being conscious implies one’s own existence (the Cogito)—consciousness carries within it the knowledge of the existence of a self. Putting these two thinkers together, we can say that being conscious carries a double existential implication: it implies the existence of a subject of consciousness and the existence of something other than the subject. It is existentially committal in two respects. Possibly these intimations are misleading (illusions etc.), but they are real intimations nonetheless. Consciousness posits a duality of existences. The suggestion is that these are universal features of consciousness, as Brentano and Descartes supposed; they are necessary and definitive. I think that is basically right, but I won’t here go into the pros and cons. The important point is that conscious states are being-directed while non-conscious states are not (being square doesn’t imply the existence of anything). We can see this in the grammar: to be consciously seeing (say) is for a subject to see an object—there is no subject-less seeing of non-objects.
What about the feeling part? I intend by this word to capture the primitiveness of consciousness in its most basic form—it is a primordial type of feeling. It is not a judgment or a mental act or a belief or an emotion; it isn’t “conceptual”. To be conscious is to feel a certain way—to feel consciously. Thus consciousness is rightly classified as a sensation: whenever an organism is in a conscious state it has a characteristic sensation, the sensation of consciousness. There are sensations of red and sensations of pain, but there is also the sensation of consciousness itself. You can feel this sensation in yourself during your waking hours; it attends your every conscious move. A being might not this have this sensation, in which case it would not be conscious. If you attend now to your visual experience, you will detect various visual sensations, but in addition to these you will find the sensation of consciousness itself. This is why you are aware of your consciousness—because you have sensation of consciousness that you know about. So the feeling of being is a sensation directed toward being—you sense being, you have a sensation of it. It is not that you believe in being whenever you are conscious or that you make a judgment about it; rather, you have a primitive sensation of being. But this sensation cannot occur in the absence of consciousness, as arguably other sensations can, since it is what consciousness is—it is precisely the sensation of consciousness (the consciousness-sensation). If you have a conscious sensation of pain, say, you have both a sensation of pain and a sensation of consciousness. The latter sensation accompanies all conscious mental states uniformly despite their phenomenological variety. When you recover consciousness upon waking up you start to have a sensation that will be present throughout your waking hours—not a higher-order judgment that you keep making or a certain type of omnipresent emotion or a mental act repeatedly performed. You have the consciousness-sensation, a specific feature of mental life.
The view I am describing has points of contact with Sartre’s view of consciousness. He emphasizes the fact that consciousness essentially posits being: the for-itself aims itself at the in-itself. It is not an enclosed self-subsistent being. He doesn’t describe it as having a sensation-like character, but this claim is consistent with his analysis. What he does emphasize is what he calls the “nothingness” of consciousness—the idea that consciousness has no positive being over and above its posited objects. I won’t try to explicate this idea here, merely noting that it can be added to the account I am developing. In Sartre’s terms, consciousness harbors a negation: it is not the objects it posits. It transcends those objects, though not because it is another object, but rather because its being is to be pure other-directedness. It posits existence without being an existent thing like the things it posits—it has a kind of invisible vanishing existence: nothingness, in a word. So, following Sartre, we can say that consciousness is the feeling of being that distances itself from being: it posits being as not itself. It is the feeling of being while feeling itself not to be a being (an in-itself). Thus three notions come together in consciousness: feeling (sensation), being (existence), and negation (nothingness). These are fundamental features of our conceptual scheme, as well as of objective reality. We can therefore say, filling out our simple formula, that consciousness is the feeling of double existence that presents itself as removed from existence (transcending it) and as not itself an existent thing (except as a kind of nothingness).
There is another way to put the view I am proposing: we can speak of manifest being and non-manifest being (pure being). Inanimate objects have non-manifest or pure being: their being is not manifest to any conscious subject, save per accidens. They simply are without any necessary recognition of this fact. But in the case of conscious subjects being becomes manifest, as when we recognize our own existence in acts of consciousness. Consciousness makes our being (and other being) manifest, so it is the agent of being-manifestation. Instead of saying that consciousness is the feeling of being we can say that it is being become manifest, thus shifting the emphasis to the level of being. Consciousness is being become aware of itself. At one time being was manifest to no one, but then consciousness came about and being became manifest. Being caused being to become aware of being. Thus the feeling of being became part of being, with its characteristic structure (sensation plus being plus negation). Instead of saying that consciousness consists in a subject feeling an object we can equivalently say that consciousness consists in an object making itself manifest to a subject—the difference is one of emphasis.
An idealist would insist that there is no being without the feeling of being, possibly a feeling in God’s mind. So there is no pure being: all being derives from the feeling of being–all being is manifest being. This is another way of saying that everything is made of consciousness, so idealism can be formulated using this definition of consciousness. It is the doctrine that all being is felt being. Being consists in sensations of being, i.e. consciousness. An idea in the mind of God is a sensation of being, since God is a conscious being, though no doubt more capacious than human sensations of being. When God has the sensation that a table exists a table exists—that’s idealism under the present theory of consciousness.
How does this account relate to the idea that consciousness consists of states there is something it is like to have? This phrase is usually coupled with the idea of subjectivity, which in turn is analyzed in terms of epistemic access: a state is said to be subjective if and only if it can only be grasped by experiencing it oneself. Thus what it is like to be a bat is subjective in the sense that only beings with experiences like bats can know what kind of state is in question. Clearly this is an epistemological point concerning knowledge of conscious states (or possibly unconscious ones if they are similarly restricted in their conditions of understanding, e.g. subliminal bat perceptions). As such it belongs to a different level from the kind of constitutive conditions I have been discussing: those are internal to conscious states, part of their structure, whereas subjectivity in the sense defined concerns relational facts about knowledge of conscious states. It says they are only knowable in a certain way, i.e. from a particular “point of view”, not from any point of view. There is nothing wrong with characterizing conscious states in this epistemological way, but it should be distinguished from the search for the constitutive nature of such states. There is no incompatibility between the two; they are aiming at different things. The feeling of being that defines a particular kind of conscious state, say a bat’s echolocation experiences, is something that can only be grasped by sharing that feeling, so that subjectivity (in the sense defined) can be added to existence, feeling, and negation that characterize the inner structure of a state of consciousness. Being can be felt (and simultaneously transcended) in different ways, and these ways correspond to differences in epistemic accessibility. There are different things it’s like for organisms and these consist in different ways that being can be felt.
But that doesn’t imply that consciousness itself is a variable commodity in the sense that the property of being conscious itself varies from organism to organism. If what I said earlier is correct, that property is uniform across types of conscious state—within an organism and across organisms. It is the same sensation in all cases—the sensation of consciousness as such. In this sense we do grasp the consciousness of bats, since their consciousness consists in the same thing as ours, viz. that feeling or sensation that makes a state a conscious state. The bat’s echolocation experience is not like anything we possess, but its being conscious is just like what we possess, since that property exists in our experience too—the property precisely of being conscious. If consciousness is a type of sensation, then bats and humans share a sensation (over and above other shared sensations), namely the sensation of being conscious. What we can’t grasp is the nature of the sensory experiences that bats enjoy, but we can grasp what consciousness is for bats, because it is the same for us. All sentient beings are united by a single mental property, i.e. the sensation of being conscious. The bat feels existence by exercising its echolocation sense, and that feeling is subjective (accessible only from one “point of view”); but in addition to that it has a sense of its own consciousness—a certain type of sensation that being conscious consists in. If consciousness consisted in possessing a higher-order thought, we would get the same result, since we know what higher-order thoughts are from our own case; but the same result follows from the sensational theory of consciousness. So there is a sense in which we don’t grasp the consciousness of bats but also a sense in which we do.
What would be a good label for the view I am describing? The label “phenomenological existentialism” suggests itself: it conveys the idea of feeling and the idea of existence, as well as their joining together. But those words carry a lot of baggage and are cumbersome—is there anything catchier and more specific? How about “felt being-ism”? True, it is grammatically awkward, and true it can claim no familiar antecedent; but at least it captures the view briefly and clearly. It’s either that or we appropriate some French or German phrase that resists translation into English, a task I leave to those more linguistically adept than I am.
 There might be other such constant sensations such as a sense of your own unity or of the presence of space and time. My suggestion is that a sensation of being conscious pervades all waking life: you constantly feel your own consciousness in the mode of sensation.