Let's discuss the idea that there are no such things as properties, just lots of things which are more or less similar

**Ostrich Nominalism** (or *Austere Nominalism*) is the view that individual objects possess features without requiring any underlying metaphysical mechanism—such as universals, tropes, or resemblance classes—to ground those facts. Its adherents, most notably W. V. O. Quine and Michael Devitt, argue that taking subject-predicate propositions like "$a$ is red" as primitive is completely sufficient. The position has drawn significant critique across analytical metaphysics. Opponents argue that refusing to explain attribute agreement amounts to abandoning the core task of ontology. --- ### 1. Named Critics and Main Objections #### **David M. Armstrong: The "Head in the Sand" Critique** * **The Objection:** Armstrong famously coined the derogatory term "Ostrich Nominalism" to accuse Quineans of hiding their heads in the sand to avoid a genuine metaphysical dilemma. * **The Mechanism:** Armstrong formulates the classic **"One over Many" problem**: when two distinct particulars ($a$ and $b$) are both red, they share a genuine feature of reality. Armstrong contends that Ostrich Nominalists confuse *semantic commitment* with *ontological explanation*. Merely stating that $a$ is red and $b$ is red using predicates does not explain *in virtue of what* both objects possess the exact same nature. * **The Verdict:** To Armstrong, refusing to answer the "in virtue of what" question leaves predication as an unexplained, magical coincidence. #### **David Lewis: The Need for "Natural Properties"** * **The Objection:** While sympathetic to sparse ontologies, Lewis argued in *New Work for a Theory of Universals* (1983) that complete indifference to properties renders a metaphysical framework incapable of doing essential work in philosophy of mind, science, and semantics. * **The Mechanism:** If all predicates are ontologically equal—as Ostrich Nominalism implies—we cannot distinguish between genuine, **natural properties** (like *being negatively charged*, which ground laws of nature and objective similarities) and arbitrary, disjunctive predicates (like *being "grue"* or *being an intrinsic component of a teapot or a moon rock*). * **The Verdict:** Primitive predication is too egalitarian; without privileges for natural properties, an ontology cannot explain scientific realism or semantic content. --- ### 2. Schools of Thought & Types of Disagreement | Intellectual Tradition / Perspective | Core Critique | Proposed Alternative | | :--- | :--- | :--- | | **Immanent Realism**<br>*(e.g., D. M. Armstrong)* | Rejects the premise that predication needs no ground. Facts require **truthmakers**—entities in reality that necessitate truths. | **Universals:** Abstract or repeatable entities instantiated by particulars. | | **Trope Theory**<br>*(e.g., D. C. Williams, Keith Campbell)* | Rejects both universals and primitive nominalism. Particular objects are bundles of localized, concrete qualities (tropes). | **Abstract Particulars:** Particular rednesses that resemble one another without being an overarching universal. | | **Constructive / Reductive Nominalism**<br>*(e.g., Resemblance or Class Nominalists)* | Agrees that abstract universals should be rejected, but disputes the Ostrich claim that no reductive explanation is needed. | **Resemblance / Sets:** Explaining property possession through comparative resemblance relations or set membership. | --- ### 3. Current Debates and Live Controversies Modern debates around Ostrich Nominalism center on two primary battlegrounds in contemporary metaphysics: #### **A. Truthmaker Theory** Contemporary truthmaker theorists (such as Gonzalo Rodriguez-Pereyra) argue that for every contingent truth (e.g., "the apple is red"), there must exist something in the world that *makes* it true. Ostrich Nominalism violates the intuition that truths are grounded in *being*. Ostrich defenders counter that the concrete object itself ($a$) is the full truthmaker for "$a$ is red," denying that a separate "property-fact" is required. #### **B. Grounding and Fundamentality** With the rise of "grounding" frameworks in 21st-century metaphysics, critics argue that Ostrich Nominalism conflates *ontological commitment* (what exists) with *grounding* (what is fundamental vs. derivative). Opponents contend that even if properties do not exist as separate objects, an object’s attributes must be grounded in its microphysical structure, making primitive predication untenable as a fundamental stopping point. --- ### 4. Summary of Strength of Objections * **Strongest Critique:** The demand for **Naturalness / Eliteness** (Lewis). Pure Ostrich Nominalism struggles to explain why natural science privileges certain features (like mass and charge) over artificially constructed predicates without admitting that some properties are objectively natural. * **Unanswered Challenge:** The **Truthmaker Principle**. If "$a$ is red" and "$a$ is round" are both true of the same object, Ostrich Nominalists must either claim the object alone makes both true (which obscures the difference between color and shape) or accept primitive, ungrounded truths.