In the Science of Logic, being is determined as a form of thinking. This is not a discovery of fact, as if "being" were already given, and that the "form of thinking" was introduced as a mere modification of this fact. Rather, "being" is here a word coined to name that which marks the beginning of pure thinking. To ask "does this really capture the meaning of being?" is meaningless, because such a question already presupposes that the term "being" has a meaning which needs to be discovered.
Perhaps "we" always already understand being in a determinate way. Yet, what does "our" understanding of being have to do with being itself? Beginning from such an understanding of being is already to narrow down the focus of thinking arbitrarily. The problem then is that those who do not share this understanding might be excluded from that inquiry, and moreover one can demonstrate explicitly how each understanding excludes an alternative. There is no universality in such thinking.
Philosophy focuses on the universal in the particulars. Being is not "the most" universal, but being is nonetheless a universal, if being were to be considered philosophically. Moreover, philosophy is thinking - the essence of philosophy is to think. If one stops thinking, one stops doing philosophy. Therefore, if there is philosophy, thinking must also exist. There are, of course, other ways of being. Beings can be without thinking. But when these beings are considered philosophically, they take part in thinking by guiding thinking and by being guided by thought.
The experiment of the Science of Logic is to see how far the boundaries of thinking can be pushed. One immediate result of the opening of the Logic is this: in thinking of what is, or of being, thinking cannot help but also think of what is not, or of nothing. It is of the very essence of thinking to think of the negative, which also means that thought as such already is a negative thought.
The negative is what makes thought concrete, "for-itself" in Hegel's language. Philosophy begins with the thought "thinking is." Philosophy then asks, "given that thinking is, what must be the case such that thinking is?" There are no other beings in existence except thinking at this point. Yet, there is thinking, and moreover there is the being of thinking. Thinking cannot "be" unless there is also "being." Hence, there is being. Moreover, this being is such that it sustains thinking, or is the being of thinking. Therefore, being is here not a completely undetermined placeholder, an empty name. Rather, being is the being of thinking, and it must be so in this context.
But then thinking is not absolutely identical with being. Rather, there are other ways of being for other beings. Thinking, then, may well not be. But then, what is the ground for the possibility of the non-being of thinking? The answer is: the negation of being, nothing. Here, again, "nothing" is a determinate nothing, a negation of the being of thinking.
Philosophy begins, then, with the antinomy "thinking is" and "thinking is not." Here, "is" does not privilege presence. Rather, "is" is understood in the sense of "God is," or "nature is," or "time is," and so forth. That is, thinking is here still timeless. Whether thinking first "is" and then "is not," whether these two propositions refer to the same point in time or in different points, these are illegitimate questions, because time is not presupposed. It is possible to think of being as timeless, and since being here is understood as the being of thinking, thinking is also timeless at this point. The necessity of introducing time should become clear in the course of thinking.
The nothing of thinking is moreover not merely singular. First, there is the nothing as the absolute negation of being, a nothing which, if it were to be, would absolutely leave no room for being. This is pure nothing. Second, however, the very thoughts of a "nothing which leaves no room for being" implies the being of nothing, and this residue of being in nothing cannot be erased without erasing thinking and the nothing of thinking too. Being, then, is despite of pure nothing. Nothing has to admit of this residue, and this admission compromises its purity. Here, nothing is an existent nothing. The existent nothing negates the pure nothing, not by virtue of itself (for that would be to presuppose this existent nothing,) but by virtue of the falsity of the thought of pure nothing. Pure nothing is false because the absolute negation of being, and the full isolation of nothing, cannot help but reintroduce being, for such an absolute nothing nonetheless is.
Pure nothing and existent nothing form a new antinomy, that is, the sides imply each other and complete a new form of thinking. This antinomy already anticipates, perhaps, the problem with the notion of "carving nature at its joints." In one sense, nature does have its joints, and "blue" and green" are joint-carving whereas "grue" and "bleen" are not. However, the two pairs cannot be reduced to a mere difference in "ideology." "Grue" is a new color, and if "bleen" is to be distinguished from "grue," then that, again, is a fourth color. If "bleen," "grue," and other such variants are intelligible as colors, then these carve nature at its joints too, for nature has these joints. If nature appears as having joints independent of thought, then that is the fault of neither nature nor of thought, but of our subjective reflection on our own thoughts as they are reflected in the way nature appears to our mind. Likewise, "being" and "nothing" produce a joint, while "existent nothing" produces a third joint. The term "joint" should be understood metaphorically at best, and is probably even then too misleading and muddles the thinking that takes place at this stage. Even when applied to nature, the term "joint" is arbitrary and misleading, for who has proven that the idea of nature has "joints" anyway? If an ideology informs thought, and if nature appears according to the difference in which self-conscious thinking is informed, then ideology has to have an effect on ontology as well. The "joints" of nature are determined by thought, and so it is tautological to claim that thought carves nature at its joints.