The Logic of 'Being'

The Linguistic Root of Ontology

The primary meaning of Aristotle’s “Being” is first and foremost the copula in language—specifically in subject-predicate sentences—rather than “existence.” In Aristotle’s subject-predicate structure, the copula “is” (being) is a judgment word connecting the concepts of the subject and the predicate; it is a logical constant.

Thus, Aristotelian concepts are noun-based lexical concepts. Whether the copula “is” (being) is true or false depends on whether an inclusion relationship exists between the subject and the predicate. Viewed this way, philosophy was entangled with language (the $S$ is $P$ structure) from the very beginning. The so-called “linguistic turn” did not suddenly appear; it was always there.

Conversely, with the application of modern logic marked by Frege, the predicate becomes the protagonist. It is the key to the cohesive force of a sentence, acting as a function that yields truth or falsehood. In Frege’s work, the copula “is” disappeared, and the concept of Truth became prominent. This greatly expanded the scope of inference and broke the mold of syllogism.

The Paradox of Modern Logic

At the end, a paradox arises: while the copula “is” disappeared as a logical constant in modern logic, the introduction of quantifiers meant that the concept of “existence” became manifested in the ontological commitment of those quantifiers. By a different path, modern logic moved closer to the metaphysical study of “Being.”

The “Is” of Logic and the “Is” of Metaphysics

I. The Philosophical “Copula”

In understanding being, I emphasize Charles Kahn’s research on the Ancient Greek einai. Among its three usages—copulative, existential, and veridical—the most primary is the copulative, accounting for over 85% of usage. According to this, we should translate einai as “is” and understand it accordingly.

Critics often ask: “Even if the copulative usage exceeds 95%, can we exclude the polysemy of the word?” My response is that the primary meaning of a concept in natural language does not vanish when it becomes a philosophical concept. Kahn’s research proves that “what it is” (ti esti) is the most basic expression in Greek life. This shows the primary meaning is the copula, and “existence” evolved from it.

II. The “Is” of Logic vs. The “Is” of Metaphysics

People often believe that using “is” as a translation has a serious consequence: it turns metaphysical speculation into “pure logical analysis.” They fear that “is” is too “logical” and that philosophy shouldn’t be reduced to linguistics. However, logic has always been the primary tool for philosophy.

In Aristotle, these are perfectly unified. His logic is a subject-predicate logic centered on “is”; his metaphysics is centered on “Being qua Being”. You cannot understand his philosophy without his logic. When we look at Analytic Philosophy, the “is” is no longer a logical constant. However, “existence” becomes prominent because the existential quantifier ($\exists$) characterizes the nature of existence.

Understanding the “is” helps us see the difference between traditional and modern logic, and thus, how different logics shape different philosophies.