This paper aims to re-examine the fundamental issues of ontology. Traditional views regard ontology as the knowledge of "what existence is", but this paper proposes a different perspective: the core of ontology is not the description of existence, but the delineation of "the threshold of existence"-that is, what can be recognized as a "being" and what is left outside the threshold. This "boundary-drawing" activity is the core mechanism for the operation of ontology. This paper examines the delimitation operation of ontology in the history of philosophy, analyzes the intrinsic connection between relations and boundaries, and combines specific fields such as contemporary digital existence to demonstrate that the essence of ontology is not a statement about "what beings are", but a practice about "how beings are distinguished, identified, connected and restricted." This paper believes that relational boundaries are not an incidental issue of ontology, but the ontology itself.

1. Introduction: A neglected issue

Ontology, as the basic department of metaphysics, has traditionally been understood as the knowledge of "being." From Parmenides's declaration that "beings exist, and non-beings do not exist", to Aristotle's questioning of "Being is Being", to Heidegger's warning of "Being is Forgetfulness", ontology in the history of philosophy has always been committed to answering a basic question: "What exists?" and its corollary: "How does it exist?”

However, what this paper attempts to point out is not the answers to these questions, but a prerequisite that lurks before all ontological questions-how is "existence" itself recognized? More specifically, what allows one thing to be regarded as a "being" or a "mode of being", while something else is not recognized as a being or is classified as a "non-being"?

This question leads us to a dimension that has been neglected for a long time: ontology not only asks "what is existence", it first delineates the "threshold of existence"-it determines what can be included in the scope of ontology discussion through a series of operations of distinction, exclusion and classification, and what can be left outside the threshold. This article calls this operation an ontological "boundary-drawing activity."

This paper attempts to demonstrate that this demarcation activity is not incidental work of ontology, but the ontology itself. The essence of ontology is not a description of existence, but a practice of "how beings are distinguished, identified, connected and restricted."

2. Ontology delimitation in the history of philosophy

2.1 Demarcation of Classical Ontology

On the surface, classical ontology is asking "what is existence", but in fact it has been implementing a systematic demarcation operation:

(1) Parmenides's "existence/non-existence" realm

Parmenides established the first boundary of ontology with "to eon esti, me eon de ouk esti": the insurmountable boundary between the being and the non-being. This boundary delineates the gap between the "incredible and expressible" and the "incredible and inexpressible". As the "identity of thinking and being", beings are retained in the core area of ontological discussions; non-beings are completely expelled.

(2) Plato's "idea/phenomenon" realm

By dividing the "world of ideas" and the "world of phenomena", Plato introduced another boundary within ontology: the hierarchical distinction between real being (ideas) and derived being (phenomena). This delineation not only distinguishes between two levels of existence, but also establishes the "foundational" relationship between the former and the latter-the phenomenal world obtains the legitimacy of its existence due to its division of concepts.

(3) Aristotle's "category/non-category" realm

Aristotle's theory of categories (entity, quantity, nature, relationship, etc.) defines the framework within which "beings can be said." What is excluded from the ten categories-such as "non-existence","infinity", and "void"-is either marginalized in ontological discussions or transformed into a special way of being within the category system.

These three delimitations-existence/non-existence, true existence/false existence, and narrable existence/unnarrable existence-constitute the basic operating structure of classical ontology. Ontology does not first have a concept of "being" and then describe it; rather, before describing "what is being", it has already delineated the field of "being worthy of discussion" through a series of exclusions and distinctions.

2.2 Loose boundaries and reconstruction of modern ontology

Modern philosophy's criticism of classical ontology is essentially a questioning of its delineation:

(1) Kant's epistemological turn

Kant's key contribution to ontology was not to propose a new category of beings, but to draw a new boundary between "phenomenon" and "thing-in-itself." What is special about this boundary is that it does not distinguish between "real beings" and "false beings", but between "recognizable" and "unrecognizable" beings. Kant's ontological delimitation operation shifts the question of "being" from "what is it" to "how is it given to us".

(2) Nietzsche's dissolution of the world of "reality/representation"

Nietzsche's attack on ontology is essentially a complete deconstruction of the classic demarcation of "real world/representational world." When Nietzsche claimed that "the real world has eventually become a fable," he was saying that the boundary that separates "real being" from "superficial being" was itself constructed. There is no "being" waiting to be discovered before the demarcation; being is generated in the demarcation.

(3) Heidegger's "Being/Being" realm

The most epoch-making ontological work Heidegger did was to draw a new and at the same time the most fundamental boundary between "being" and "being". He pointed out that traditional ontology has always mistakenly regarded "being" as "being" itself, thus forgetting the dimension of "being" as "the condition that enables the being to appear." "Oblivion of existence" means ignoring this boundary.

2.3 The Multiple Boundary Practice of Contemporary Ontology

Ontology since the second half of the 20th century no longer seeks a single and fixed demarcation plan, but presents diverse boundary practices:

Process philosophy (Whitehead) regards existence as the dynamic "intake" and "connection" between "reality", and the boundary between beings is constantly generated and dissolved.

The philosophy of difference (Deleuze) no longer regards "unity" as the starting point of existence, but regards "difference" as the original condition of existence-boundaries are not predetermined by identity, but are constantly redrawn in the operation of differences.

Phenomenology (Husserl, Merleau-Ponty) reconstructs the traditional boundary of "subject/object" into a symbiotic relationship of "mutual conditioning" through the concepts of "intentionality" and "body".

These contemporary turns collectively point to a trend: the focus of ontology is shifting from "what is a being" to "how is a being related" and "how boundaries are delineated."

3. Priority of relationships: Boundaries are conditions for relationships

3.1 Being is identified in relationships

If we turn our attention from "beings themselves" to "between beings", a key fact will emerge: beings do not become beings because of certain attributes inherent in themselves, but are identified as "this one" in their relationships with other beings, through identification and differentiation at boundaries.

This view can be understood from three levels:

(1) Distinction levels: Without boundaries, there will be no differences. A being is a being first because of the identifiable differences between it and other beings. Differences are revealed through boundaries.

(2) Connection level: The boundary is not only the separation line, but also the contact surface. For two beings to have a relationship, they must first have an interface that can be contacted-that is, a boundary. Without boundaries, there is no relationship; without relationships, beings are completely isolated, and completely isolated beings are unrecognizable.

(3) Naming level: When an existence is named, it means that it has been classified into a certain category, and the category itself is the result of a set of demarcation operations. "Entity","attribute","relationship","process"-these ontological category systems are nothing more than a set of systematic demarcation standards.

3.2 Dual functions of borders

Boundaries serve a dual function in ontology:

Separating function: Separating "this" and "that", allowing the existence to obtain a recognizable identity.

Connecting function: enables "this" and "that" to have a relationship, making interaction between beings possible.

This leads to a corollary: boundaries are never simply "dividing lines", but the place where relationships occur. Delimitation is not an exclusive operation, but there are conditions for its development. It is precisely because there are boundaries between beings that existence is not a chaotic sea of indifference, but a field with structure, hierarchy, and meaning.

4. Practical scope of demarcation activities

In order to concretize the above philosophical arguments, this paper selects several contemporary practice fields to show how demarcation activities play a role in the issue of "how beings are identified."

4.1 Sovereign boundaries in digital existence

When a user of a digital system decides to keep data "locally" rather than "in the cloud," he is not only making technical choices, he is also drawing an ontological boundary. This boundary distinguishes digital existence into two categories: one is "sovereign being" based on local hardware, with local inference as its operation mode, and with direct user control as its existence condition; the other is "entrusted being" based on remote servers, with network transmission as its operation path, and with service provider control as its existence condition.

The key to this demarcation activity is not "which of the two types of beings is more real", but how the boundary itself is delineated, perceived, and maintained. The technical concept of data sovereignty appears as the "delineation of the territory of existence" at the ontological level under the ontological framework-users establish it for a digital existence by configuring storage paths, setting firewall rules, and choosing whether to allow networking."way of existence".

4.2 Ontological presuppositions of agents

When building an agent, configurations such as system prompt words, knowledge base settings, tool call permissions, etc. -these superficial technical settings-are actually pre-setting its "existence structure" for a "digital entity" that has not yet run:

The system prompt word presupposes its "identity boundary"-how it understands itself and how it is understood by users.

The knowledge base predetermines its "memory boundaries"-which information can be called and which information is excluded.

Tool invocation permissions preset its "action boundaries"-what it can do, what it cannot do, and how to expand its scope of action.

The metacognition architecture presupposes its "thinking boundaries"-how it organizes its own reasoning process and reflects on its own output.

The essence of these presuppositions is to answer a traditional ontological question: "How does this being exist?" But its answer is not through philosophical speculation, but through code configuration-this is a new way for ontological issues to unfold in the digital age.

4.3 Philosophical significance of blurred boundaries

It is worth noting that the core focus of the above-mentioned practices is often not on "areas where boundaries have been clearly delineated", but on "vague areas at the boundaries":

Is it possible for local data to flow out across borders without the user's knowledge? (Can the boundary be penetrated?)

Can local systems establish temporary connections with cloud systems when needed? (Can controllable channels be set up at the boundary?)

Does the agent's "self" boundary move as it learns and interacts? (Is the boundary dynamic?)

This continued focus on "blurred boundaries" points to the most cutting-edge issue of contemporary ontology: existence is not either or, but a coexistence of "both here and there". The power of a boundary lies not in its absolute impenetrability, but in its being both a separation and a connection-it remains a "negotiable interface" rather than an "incommensurable crack."

5. Conclusion: Ontology is boundary operation

Back to the core proposition of this article:

The essence of ontology is not a description of "existence", but an operation of "threshold of existence". The core mechanism of this operation is demarcation-delineation of what can be recognized as beings and what is left outside the threshold; and delineation of how beings relate and how boundaries are perceived and adjusted.

Traditional ontology seeks a set of fixed demarcation standards-a formal definition of "the being is..." This paper attempts to show that boundaries are not given a priori, but are constantly delineated in the mutual relationship of beings. Every time a relationship is established, it redefines boundaries; every time a boundary is moved, it redefines what constitutes "existence." Delimitation is not a preparatory work for ontology, but the ontology itself.

If this inference holds, ontology is no longer a set of static statements about "ultimate reality" but a set of dynamic practices about "how beings are distinguished, identified, connected, and restricted." It focuses not on "what a being is" but "how a being is placed in its being"-that is, how the threshold of being is set, how it is perceived, and how it is crossed.

references

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