Continuing from part one on The Phenomenology of Spirit (1807), focusing on ch. 2 "Perception" after we quickly conclude our treatment of ch. 1 "Sense Certainty."
Does Hegel's claim about the inadequacy of perceptual knowledge also indicate an incoherence in traditional metaphysical accounts? Since much of Hegel's emphasis in considering perception is the relationship between an object's various properties, it does look like phenomenology is supposed to tell us not just about how we should describe what we know, but about how the world could possibly be. As Locke pointed out, we don't have any direct experience of a bare, property-less substance that would then serve to house and unify all the properties, yet the idea of a mere bundle of properties that just hang around each other for no reason is also deeply unsatisfying.
A key point in this section (and throughout Hegel's book) is a determinate negation: For anything to emerge as a definite thing, it needs to be defined as not something else, which then set it in relation to that else, and these relations are therefore properties (i.e. parts) of the first thing. So you were trying to distinguish something, but in doing so, you've created a unity between the thing and its opposition. This is one way to describe the dialectic not just as a progression of theories about knowledge, but in a physical manifestation. So the various properties of, for instance, a heap of salt are related to each other in this sort of unified opposition. You might think (at the beginning of the Perception chapter) that you're perceiving a unified thing, which would mean that its Oneness makes it indifferent to its properties (meaning that even a change in properties wouldn't change which thing we're pointing out; remember, we're coming out of the sense-certainty chapter that was concerned with the alleged perception of and reference to a particular, and so in this section, we're still doing that, although we acknowledge that there are what Hegel calls "sensuous universals" involved), but because the properties end up actually related to each other after all, it must be the thing that's relating them, so it isn't actually a One but is a Many (a unity with the properties it relates).
Ambiguity in what properties are actually associated with the thing I'm referring to allows us according to Hegel to talk about perceptual error. For instance, I thought I was looking at a horse, but it was just a picture of a horse, and so didn't have the three-dimensional shape (not to mention the liveliness) that I thought I perceived.
Ultimately all vacillation in how we're understanding the objects we perceive leads according to Hegel to seeing the essence of that perception as being this movement within the mind, i.e. the vacillation, which means that perception involves not just direct contact with particulars, or indirect contact with them through sensuous universals, but it involves the Understanding and its abstract concepts ("unconditioned universals").