Hegel claims that we can trace successive levels of consciousness, form the lowest to the highest, and this is what he does in the Phenomenology of Spirit which can be described as the history of consciousness. If we consider the mind and its activity in themselves without relation to the object, we are concerned with psychology. If however we consider the mind as essentially related to the object (external or internal) we are concerned with consciousness. Phenomenology is the science of consciousness in this sense (and hence distinct from psychology as Hegel conceived of psychology). Hegel begins with natural unscientific consciousness and then proceeds to trace the dialectical development of consciousness, showing that lower levels are subsumed in the higher ones until we reach absolute knowledge.
Hence the Phenomenology of Spirit is an introduction to philosophy, systematically tracing the development of consciousness up the level of what we properly call philosophical consciousness (reason; knowledge of the Absolute). However the book is definitely not an introduction to philosophy in the sense that it is a preparation for doing philosophy since Hegel deemed that impossible. However the book is a sustained effort in philosophical reflection on the phenomenon of the origins of philosophical consciousness. [ Hegel’s entire system finds a place for the phenomenology of consciousness as can be seen when he treats religion and art and politics as different phases of consciousness.]
Hegel’s Phenomenology of Spirit systematically traces the development of consciousness up to the level of philosophical consciousness which is philosophical reflection on its own origins. Hegel does this in three parts:
(1) the first phase of consciousness is consciousness (Bewusstsein) of the object as a sensible thing standing over and against the subject.
(2) The second phase is that of self-consciousness (Selbstbewusstsein) which essentially involves consciousness of the other (social or communal consciousness).
(3) The third phase is that of Reason (Vernunft) which is the unity namely the synthesis of objectivity and subjectivity (of the first two parts) on a higher level.
Each phase has its own subdivisions but Hegel begins with the spontaneous attitude of consciousness and then proceeds to analyze it. In this analysis the mind is compelled to proceed to the next level as a more considered attitude towards consciousness.
Thus, Hegel begins with sense certainty (naïve realism) as the uncritical apprehension of sense objects which appears to naïve consciousness as both the simplest and richest form of knowledge, naïve consciousness feels directly acquainted, through sense apprehension, with a particular thing. The trouble is that when we try to say what it is we know in this direct acquaintance (describe of the particular thing) we find ourselves using universals which are applicable to other things as well. We can of course try to pin down the object by using words like “this”, “that” “here”, “now” and some accompanying ostensive gesture but a moment later these same words apply to other objects. Indeed, Hegel argues that indexicals (“this”, “that”) do not have genuine “meaning” (are not universals).
If Hegel is here calling attention to the critical role of language, his main concern is epistemological. His claim is that sense-certainty is bogus (it is always of the “here and now”) and for sense certainty to eventually become knowledge it must pass into a level of perception for which the thing is conceived as the independent center of distinct properties and qualities. But analysis of this perceptual level of consciousness shows that as long as we remain at the level of sense it is impossible to reconcile the elements of unity and multiplicity which are postulated by this view of objects. The mind therefore passes through various stages to the level of scientific understanding which invokes meta-phenomenal or unobservable entities to explain sense phenomena.
For example, the mind sees sense-phenomena as manifestations of hidden forces but Hegel maintains that the mind cannot rest there and proceeds instead to the ideas of laws. Yet natural laws are ways of ordering and describing phenomena (perceptual appearance, like Kant’s); they (laws of science) are not explicative. Hence, they cannot explain sense-phenomena (sense of being directly acquainted with the world). Hegel obviously does not deny that the concept of natural laws is not useful at an appropriate level but it does not give the sort of knowledge which the mind is seeking.
In the end the mind sees that the whole realm of the meta-phenomenal which has been invoked to explain sense phenomena is a product of the understanding itself (cf. Kant). Consciousness is therefore turned back on itself as the reality behind the veil of phenomena and becomes self-consciousness.