1: All experience is consciousness of some content.
Whatever is experienced is either consciousness, or something of which one is conscious of. If there was something that, by definition, was utterly outside of the domain of consciousness, there could be no experience of it. Even just thinking such a possibility is an option only insofar as there is consciousness of this thought. Conscious experience thus defines the whole domain of experience or reality.
If one stops here, however, the result will be some form of solipsism (in which consciousness is interpreted from the point of view of a particular subject of experience, who is assumed to be the ground, source, or owner of consciousness). In other words, if one stops here, then the whole of reality is reduced to my own conscious experience of the world. Solipsism raises many issues, the most important of which is that it neglects the crucial fact stated in 2.
2: Consciousness is not the content of consciousness.
Whatever the content of consciousness is, consciousness as such (the fact that there is consciousness of this content) is different from that content. That in virtue of which anything can appear, cannot in itself be part of what appears (in the same way in which one can see through the eye, but cannot see one's own eye). Whenever something appears, and whatever appears, precisely because it appears, it also presupposes that there is an appearing of it (a consciousness of it). Consciousness itself can appear as an object of experience (as a content) only insofar as there is a broader consciousness within which that objectified consciousness appears.
Since all contents are determinate (they are this rather than that, they are different from one another, specified, qualified, discernible to some extent), and since consciousness is essentially different from any content, consciousness itself is not determinate, it has no qualities, no specific marks (except or besides the sheer fact of being that in virtue of which everything else can manifest). In this sense, consciousness can only be ‘pure consciousness’. Since intentionality (about-ness, or being about something) is also something that appears as a content, pure consciousness lacks intentionality, and by itself is not about anything in particular, not even about itself. And given that subject and object are correlative notions, both based on a form of intentionality, it is only improperly speaking that one can consider pure consciousness as a 'subject'.
If one stops here, however, one remains locked within the domain of absolute idealism, in which the whole of reality is reduced to pure consciousness, and to consciousness only. Moreover, given the difference between pure consciousness and its contents, the latter can be seen as derivative, even illusory, and possibly dismissed as something from which one should ‘wake up’. Especially this latter ‘illusionistic’ turn is problematic, mostly because it ignores what stated in 3.
3: Contents of consciousness are expressions of consciousness.
Since the whole of experience is nothing but consciousness, contents of experience are necessarily appearing within consciousness (because of 1). Moreover, they could not possibly originate or come from anything else (for the same reason). Hence, contents are as real as consciousness itself. They are both made of the same stuff, albeit expressed in two different ways. Or else, contents are expressions of consciousness, in the sense that they manifest the possibilities of being-conscious that are implicit within the ground of pure consciousness.
If one stops here, however, it will seem as if consciousness moves only in one way, towards its own expression manifested in the manifoldness of contents. But since contents are essentially different from consciousness (because of 2), contents as such do not manifest the nature of pure consciousness, and absorption in contents is in fact a condition in which pure consciousness is forgotten and hides itself. This is a form of bondage (since distorts the understanding of reality). If the directionality of consciousness was only one-sided, aiming exclusively at its own expression in contents, consciousness would necessarily bound and hide itself forever. But this is false, because of 4.
4: Self-consciousness is its own identity-and-difference to contents.
When there is only consciousness of contents, then there is solipsism (for 1). If there is only consciousness of the difference between consciousness and contents, then there is absolute idealism (for 2). Both views are partial, because contents are different from consciousness (vs. solipsism, because of 2), and at the same time they are also identical with consciousness (vs. absolute idealism) in the sense that they are both made of the same stuff (because of 3). Hence, consciousness and contents are body identical and different, or rather, they are related through 'identity-and-difference'. When there is consciousness of that, then consciousness is conscious of its own proper nature (its being identical-and-different from its own contents). Hence, there is self-consciousness, which includes both consciousness and its contents, both their identity and their difference, in a supreme unity of experience. From this, 5 follows.
5: Self-consciousness, the unity of experience, is bliss.
PS: These reflections are a remaking and emendation of a similar thread of thoughts, articulated four years ago here.