According to Houlgate, philosophers had traditionally thought of thought in terms of "logical possibility", "necessity", "contradiction" and "non-contradiction". For Hegel, however, "thinking must at least be the thought of is" (98). This, to put it simply, must come before the more logical ways of seeing thought or cognition. That is
"before we can arrive at a determinate understanding of any possibility, actuality, or necessity – that is, of anything at all – we must at least think of such an undetermined possibility, actuality, or necessity as being whatever it is." (98)
So this Continental interest in being isn't "anti-intellectual" (as it is often seen in Anglo-American analytic philosophy). It's more a position of the prior nature of being before it's conceptualised or embodied within various logical contexts.
To begin with, Houlgate stresses what Being is not. For example, we
"cannot simply assume in advance that it means 'existing' or 'having a certain identity', or 'subsisting over time'.” (98).
All these things, therefore, must come after the beinghood of Being is established. They're ways Being can be: being can exist, have a certain identity, or can subsist over time. Being, therefore, is a broader term than, say, existence, identity, etc. Or, to put it another way, Being (or a being) needn't exist and certainly needn't be alive. We can say here that Being is anything than can be the subject of thought before any philosophical or logical determinations.
Not unlike Edmund Husserl later, Hegel was interested in the nature of "presuppositional" thought. As Houlgate puts it, the
"first category we come across when we presuppose nothing whatsoever about thinking – except that it is thinking – is thus the simple category of being". (98)
Or as Hegel puts it, being "without any further determination" (1812-16; 1832).
Clearly, then, this Being (or "pure being"), whatever it is, seems a pretty hard thing to think about. Hegel himself acknowledges this very indeterminateness of Being. In a sense, the point of Being is its very indeterminateness; or, as Tractatus Wittgenstein might have put it, its "un-analysability". Houlgate too accepts this paradoxical nature of pure Being. He says that because
"of its sheer indeterminateness, the thought of pure being is in fact completely and utterly vacuous".
So, again, Hegel fully acknowledges the emptiness of pure Being; or, alternatively, of the concept (or notion) of pure Being.
However, that indeterminateness of being had many interesting consequences for Hegel. Again, Houlgate admits that pure Being is "indistinguishable from the thought of nothing whatsoever" (99). But to Hegel this acceptance of pure Being’s essential vacuity has many interesting consequences; primarily its relation to genuine nothingness and the nature of becoming/individuation.
So the first category of Being "thus immediately gives rise to a second category" (99) – that of Nothingness. And from this stark duality of Being and Nothingness, another essential and fundamental category immediately arises: Becoming. So the category of nothingness is very like the category of pure Being. As Houlgate puts it:
"Nothingness, like being, itself is sheer emptiness and lack of determinacy, and so is itself nothing but indeterminate be-ing."
Though, again, the Being/Nothingness duality itself brings with it a new trinity: Nothingness/Becoming/Being. In terms of our cognitive position on the Being/Nothingness duality, "thought of being slides immediately into the thought of nothing" (99). So, as a consequence of this, the Being/Nothingness relation is not a genuine duality at all for the Hegelian philosopher. As Hegel puts it:
".... their truth is, therefore, this movement of the immediate vanishing of the one in the other: becoming, a movement in which both are distinguished, but by a difference which has equally immediately dissolved itself." (99)
So just as Hegel rejected all the primary dualisms of Western philosophy; so, in a sense, he also rejects his own Being/Nothingness duality by emphasising the category Becoming. We now have a Nothingness/Being/Becoming trinity; rather than a duality between Being and Nothingness.
To reiterate. In Hegel’s presuppositionless philosophy of thought we begin with the basic category of ‘is’ or Being. Then "turns out that to think is also minimally to think “becomes”’ (99). From this inter-fluidity of basic categories of thought various things applicable to other areas of ontology and philosophy follow. This acknowledgement of the fluidity of categories or concepts (or of what they express) can be seen in the way that Hegel "follows the footsteps of Heraclitus and anticipates the thinking of Nietzsche" (99). Most importantly, this Being/Nothingness/Becoming trinity exemplifies Hegel’s well-known account of dialectical processes. Hegel himself defines his notion of dialectical processes thus: "the dialectical movement as the self-sublation of finite determinations" (1830, 99). Despite this ostensibly pretentious flux of technical terms, Hegel himself writes that he's essentially describing "their [categories] passing into their opposites" (Hegel, 1830). In other words, "finite determinations" (or categories) are always parasitical on other determinations (or categories/concepts). This preempts Jacques Derrida’s stress on the fluidity of what he calls "binary oppositions".