Take a simple sentence: “Maria built a house.” It’s clean, clear, and communicates a complete thought. But language is rarely so simple. We can expand that sentence almost endlessly: “Maria quickly built a house on the hill with recycled materials last summer.”

How does our grammar handle this? It seems like all those extra details—”quickly”, “on the hill”, “with recycled materials”—are modifying the action of building. But what, exactly, are they attaching to? For decades, this seemingly simple question posed a significant puzzle for linguists and philosophers of language. The answer, as it turns out, lies in a hidden component of meaning tucked inside every action verb: an event.

This is the core idea behind event semantics, a theory that revolutionized how we understand the meaning of sentences. It argues that a verb like “build” doesn’t just link a subject (“Maria”) to an object (“a house”). It also introduces an abstract ‘event’—a specific instance of building—that all the other details of the sentence can latch onto.

The Old Puzzle: Where Do Adverbs Go?

Before the widespread adoption of event semantics, a common approach in formal linguistics was to treat a verb as a relation between its participants. For our simple sentence, the meaning could be represented like this:

build(Maria, a house)

This says that “build” is a two-place relation connecting the builder and the thing built. This works well enough for the basic sentence, but it falls apart as soon as we add modifiers (adverbs and prepositional phrases).

Where does “quickly” fit into build(Maria, a house)? Is “build quickly” a completely different verb from “build”? If so, we’d need a new relation for every possible adverb: build_quickly(Maria, a house), build_on_a_hill(Maria, a house), and even a monstrous build_quickly_on_a_hill_with_recycled_materials(Maria, a house).

This is incredibly inefficient and doesn’t capture the intuition that these are all variations of the *same core action*. We’re not learning thousands of different verbs; we’re just adding optional details. The old model had no elegant place to put them.

Enter the Event: A Semantic Revolution

In the 1960s, the philosopher Donald Davidson proposed a groundbreaking solution. He suggested that sentences about actions are not just about the participants but are fundamentally about the action *itself* as a concrete entity in the world. He called this entity an event.

Under this new model, the sentence “Maria built a house” means something more like:

“There exists an event (let’s call it ‘e’), such that ‘e’ was a building event, the agent of ‘e’ was Maria, and the theme (thing built) of ‘e’ was a house.”

In the notation of formal semantics, it looks something like this:

∃e [ building(e) & Agent(e, Maria) & Theme(e, a house) ]

This might look more complicated, but it’s incredibly powerful. The verb “build” is no longer a relation between two arguments. Instead, it introduces an event variable, `e`, and the rest of the sentence describes the properties of that event. Maria and the house are linked to the event through thematic roles like Agent (the doer) and Theme (the thing affected).

Solving the Adverb Puzzle with Style

With the event variable `e` at the center, the adverb puzzle simply dissolves. Adverbs and adverbial phrases are no longer homeless additions; they are simply more descriptions of the event `e`.

Let’s look at our complex sentence again. Each modifier just adds another piece of information to our description of the building event:

• “Maria built a house.”
  
  ∃e [ building(e) & Agent(e, Maria) & Theme(e, a house) ]
• “Maria built a house quickly.”
  
  ... & Manner(e, quick)
• “…on the hill.”
  
  ... & Location(e, on the hill)
• “…with recycled materials.”
  
  ... & Instrument(e, recycled materials)
• “…last summer.”
  
  ... & Time(e, last summer)

All these additional phrases are conjoined to the main assertion. They are predicates of the event `e`. This is why you can add them, remove them, or shuffle their order (for the most part) without destroying the core meaning of the sentence. They all modify the same central event, like spokes on a wheel.

Unpacking the Verb: Argument Structure

Event semantics also gives us a clearer picture of argument structure—the set of participants required by a verb.

The verb’s core meaning dictates which thematic roles are mandatory. For “build”, you need a builder (Agent) and something built (Theme). You can’t just say, “*Maria built.” The sentence feels incomplete because the `Theme` role is missing. These required roles are called arguments.

In contrast, roles like `Location`, `Manner`, and `Instrument` are optional. They add richness but aren’t required by the verb “build.” These optional modifiers are called adjuncts.

Event semantics provides a beautiful framework for this distinction:

• Arguments are the participants specified by the verb’s core event definition (e.g., `building(e, Agent, Theme)`).
• Adjuncts are extra predicates you can add to modify `e` (e.g., `Location(e)`, `Time(e)`).

This explains why “He ran” is a complete sentence (run requires an Agent but not much else), while “*She put the book” is not (put requires an Agent, a Theme, and a Location).

More Than Just Grammar: Events in the Mind

Perhaps the most profound implication of event semantics is that it isn’t just a clever linguistic formalism. It seems to reflect how we actually conceptualize and remember actions. When you witness an event, you don’t just encode a simple relation between a doer and a done-to. You mentally represent the entire scenario: who did what, where, when, how, and why.

Your memory of “Maria built a house” is not a sterile fact `build(Maria, house)`. It’s a memory of a specific *event* of building, complete with mental images of the location, the tools used, and the speed of construction. Our language, structured around a central event, seems perfectly tailored to communicate these rich, multi-faceted mental representations.

The Event Hiding in Plain Sight

So, the next time you use an action verb, remember what’s hiding within it. It’s not just a word; it’s a conceptual anchor for a whole story. This hidden ‘event’ is the silent hero of the sentence, effortlessly holding together all the details that bring an action to life. By making this one small change to our model of meaning—from `verb(x, y)` to `∃e [ verb(e) & … ]`—we unlock a deeper understanding of grammar, meaning, and the elegant connection between language and the human mind.